This is a list of free and open-source software packages, computer software licensed under free software licenses and open-source licenses. Software that fits the Free Software Definition may be more appropriately called free software; the GNU project in particular objects to their works being referred to as open-source.^[1] For more information about the philosophical background for open-source software, see free software movement and Open Source Initiative. However, nearly all software meeting the Free Software Definition also meets the Open Source Definition and vice versa. A small fraction of the software that meets either definition is listed here. Some of the open-source applications are also the basis of commercial products, shown in the List of commercial open-source applications and services.

• OpenCog – A project that aims to build an artificial general intelligence (AGI) framework. OpenCog Prime is a specific set of interacting components designed to give rise to human-equivalent artificial general intelligence.

• AForge.NET – computer vision, artificial intelligence and robotics library for the .NET framework
• OpenCV – computer vision library in C++

• See List of open-source machine learning software
• See Data Mining below
• See R programming language – packages of statistical learning and analysis tools

• TREX – Reactive planning

• Robot Operating System (ROS)
• Webots – Robot simulator

• CMU Sphinx – Speech recognition software from Carnegie Mellon University
• Emacspeak – Audio desktop
• ESpeak – Compact software speech synthesizer for English and other languages
• Festival Speech Synthesis System – General multilingual speech synthesis
• Modular Audio Recognition Framework – Voice, audio, speech NLP processing
• NonVisual Desktop Access – (NVDA) Screen reader, for Windows
• Text2Speech – Lightweight, easy-to-use Text-To-Speech (TTS) Software

• Dasher – Unique text input software
• Gnopernicus – AT suite for GNOME 2
• Virtual Magnifying Glass – A multi-platform screen magnification tool

• FreeCAD – Parametric 3D CAD modeler with a focus on mechanical engineering, BIM, and product design.
• LibreCAD – 2D CAD software using AutoCAD-like interface and file format.
• SolveSpace – 2D and 3D CAD, constraint-based parametric modeler with simple mechanical simulation abilities.
• BRL-CAD – a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system.
• OpenSCAD – A scripting based 3D CAD software.
• Open Cascade Technology (OCCT) – a CAD kernel for 3D CAD, CAM, CAE, etc.
• Blender
• Wings 3D
• Art of Illusion
• MeshLab
• MakeHuman
• Sweet Home 3D

• Gmsh – A three-dimensional finite element mesh generator with built-in pre- and post-processing facilities.

• Electric
• FreePCB
• Fritzing – a CAD software for the design of electronics hardware to build more permanent circuits from prototypes
• gEDA
• GNU Circuit Analysis Package (Gnucap)
• Icarus Verilog
• KiCad – a suite for electronic design automation (EDA) for schematic capture, PCB layout, manufacturing file viewing, SPICE simulation, and engineering calculation
• KTechLab
• Magic
• Ngspice
• pcb-rnd
• Oregano
• Quite Universal Circuit Simulator (QUCS)
• Verilator
• XCircuit

• Blender – 3D computer graphics software toolset used for creating animated films, visual effects, art, 3D printed models, and motion graphics.
• FreeCad, equivalent of Blender, towards to mechanical engineering
• OpenFOAM – open-source software used for computational fluid dynamics (or CFD).
• FlightGear - atmospheric and orbital flight simulator with a flight dynamics engine (JSBSim) that is used in a 2015 NASA benchmark^[2] to judge new simulation code to space industry standards.
• SimPy – Queue-theoretic event-based simulator written in Python
• Salome – a generic platform for Pre- and Post-Processing for numerical simulation

• ClamAV – cross-platform antimalware toolkit written in C and C++, able to detect many types of malware including viruses
• ClamWin – free and open-source antivirus tool for Windows and written in C, C++
• Lynis – Security audit tool (set of shell scripts) for Unix and Linux

• MyDLP

• dvdisaster
• ddrescue
• Foremost
• PhotoRec
• TestDisk

• The Coroner's Toolkit
• The Sleuth Kit

• USBKill
• Tails
• BusKill

• DBAN
• srm

• Bouncy Castle
• GnuPG
• GnuTLS
• KGPG
• NaCl
• OpenSSL
• Seahorse
• Signal
• stunnel
• TextSecure
• wolfCrypt
• 7-Zip

• dm-crypt
• CrossCrypt
• FreeOTFE and FreeOTFE Explorer
• eCryptfs
• VeraCrypt

• Firewalld
• Uncomplicated Firewall (ufw)
• Firestarter
• IPFilter
• ipfw
• iptables
• nftables
• M0n0wall
• PeerGuardian
• PF
• pfSense
• OPNsense
• Rope
• Shorewall
• SmoothWall
• Vyatta
• VyOS

• Snort – Network intrusion detection system (IDS) and intrusion prevention system (IPS)
• OpenVAS – software framework of several services and tools offering vulnerability scanning and vulnerability management

• Cyberduck – macOS and Windows client (since version 4.0)
• Lsh – Server and client, with support for SRP and Kerberos authentication
• OpenSSH – Client and server
• PuTTY – Client-only

• Bitwarden
• KeePass
• KeePassXC (multiplatform fork able to open KeePass databases)
• Password Safe
• Mitro
• Pass

• BleachBit

• Apache Cassandra – A NoSQL database from Apache Software Foundation offers support for clusters spanning multiple datacenter
• Apache CouchDB – A NoSQL database from Apache Software Foundation with multi-master replication
• MariaDB – A community-developed relational database management system with pluggable storage engines and commercial support
• PostGIS – Adds support for geographic objects to the PostgreSQL as per Open Geospatial Consortium (OGC)
• PostgreSQL – A relational database management system emphasizes on extensibility and SQL compliance and available for Windows, Linux, FreeBSD, and OpenBSD

• Environment for DeveLoping KDD-Applications Supported by Index-Structures (ELKI) – Data mining software framework written in Java with a focus on clustering and outlier detection methods
• FrontlineSMS – Information distribution and collecting via text messaging (SMS)
• Konstanz Information Miner (KNIME)
• OpenNN – Open-source neural network software library written in C++
• Orange (software) – Data visualization and data mining for novice and experts, through visual programming or Python scripting. Extensions for bioinformatics and text mining
• RapidMiner – Data mining software written in Java, fully integrating Weka, featuring 350+ operators for preprocessing, machine learning, visualization, etc. – the prior version is available as open-source
• Scriptella ETL – ETL (Extract-Transform-Load) and script execution tool. Supports integration with J2EE and Spring. Provides connectors to CSV, LDAP, XML, JDBC/ODBC, and other data sources
• Weka – Data mining software written in Java featuring machine learning operators for classification, regression, and clustering
• JasperSoft – Data mining with programmable abstraction layer

• ParaView – Plotting and visualization functions developed by Sandia National Laboratory; capable of massively parallel flow visualization utilizing multiple computer processors
• VTK – Toolkit for 3D computer graphics, image processing, and visualisation.

• GParted
• FIPS (computer program)
• TestDisk

• ApexKB, formerly known as Jumper
• Lucene
• Nutch
• Solr
• Xapian

• Konstanz Information Miner (KNIME)
• Pentaho

• PeaZip
• 7-Zip

• OpenAFS – Distributed file system supporting a very wide variety of operating systems
• Tahoe-LAFS – Distributed file system/Cloud storage system with integrated privacy and security features
• CephFS – Distributed file system included in the Ceph storage platform.

• Collabora Online Draw and Writer – Enterprise-ready edition of LibreOffice accessible from a web browser. The Draw application is for flyers, newsletters, brochures and more, Writer has most of the functionality too.^[3]
• Scribus – Designed for layout, typesetting, and preparation of files for professional-quality image-setting equipment. It can also create animated and interactive PDF presentations and forms.
• LyX – A "What You See Is What You Mean" document creation system, LyX makes use of the LaTeX markup macro system for TeX, allowing the elegant creation of documents which match up with the layouts in it for various document classes.

• Calibre – Cross-platform suite of ebook software
• Collabora Online Writer – Enterprise-ready edition of LibreOffice accessible from a web browser. Allows exporting in the EPUB format.^[4]
• Sigil – Editing software for e-books in the EPUB format

• ATutor – Web-based Learning Content Management System (LCMS)
• Chamilo – Web-based e-learning and content management system
• Claroline – Collaborative Learning Management System
• DoceboLMS – SAAS/cloud platform for learning
• eFront – Icon-based learning management system
• H5P – Framework for creating and sharing interactive HTML5 content
• IUP Portfolio – Educational platform for Swedish schools
• ILIAS – Web-based learning management system (LMS)
• Moodle – Free and open-source learning management system
• OLAT – Web-based Learning Content Management System
• Omeka – Content management system for online digital collections
• openSIS – Web-based Student Information and School Management system
• Sakai Project – Web-based learning management system
• SWAD – Web-based learning management system

• FlightPath – Academic advising software for universities

• Tux Paint – Painting application for 3–12 year olds
• GCompris – Educational entertainment, aimed at children aged 2–10

• Alpheios Project
• Anki (software)
• FirstVoices
• Kiten

• Linux - Unix-based general use OS
• UberStudent – Linux-based operating system and software suite for academic studies
• MAX (operating system)
• Edubuntu

• Vym (software)
• Compendium (software)
• Gnaural – Brainwave entrainment software

• Kiwix: A free and open-source offline web browser that allows users download Wikipedia entire content and use for offline learning, later was expanded with repositories for Wikimedia Foundation, public domain texts from Project Gutenberg, many of the Stack Exchange sites, and other resources.
• OpenStreetMap: OpenStreetMap was developed in 2004, it uses Open data and users data input through Crowdsourcing and Web mapping to create a complete and downloadable alternative to other online maps, this allow users to enter data when there is no data available due to lack of governance and economic interest or due lower population of the places mapped

• KTouch – Touch typing lessons with a variety of keyboard layouts
• Tux Typing – Typing tutor for children, featuring two games to improve typing speed

• GnuCash – Double-entry book-keeping
• HomeBank – Personal accounting software
• KMyMoney – Double-entry book-keeping
• LedgerSMB – Double-entry book-keeping
• RCA open-source application – management accounting application
• SQL Ledger – Double-entry book-keeping
• TurboCASH – Double-entry book-keeping for Windows
• Wave Accounting – Double-entry book-keeping

• Bitcoin – Blockchain platform, peer-to-peer decentralised digital currency
• Ethereum – Blockchain platform with smart contract functionality

• CiviCRM – Constituent Relationship Management software aimed at NGOs
• iDempiere – Business Suite, ERP and CRM
• SuiteCRM – Web-based CRM

• Adempiere – Enterprise resource planning (ERP) business suite
• Apache OFBiz – A suite of enterprise applications from Apache Software Foundation
• Compiere – ERP solution automates accounting, supply chain, inventory, and sales orders
• Dolibarr – Web-based ERP system
• ERPNext – Web-based open-source ERP system for managing accounting and finance
• ERP5 – Single Unified Business Model based system written with Python and Zope
• iDempiere – Fully navigable on PCs, tablets and smartphones driven only by a community of supporters
• Ino erp – Dynamic pull based system ERP
• JFire – An ERP business suite written with Java and JDO
• LedgerSMB – A double entry accounting and ERP system written with Perl
• metasfresh – ERP Software
• Odoo – Open-source ERP, CRM and CMS
• Openbravo – Web-based ERP
• Tryton – Open-source ERP

• OrangeHRM – Commercial human resource management

• Mifos – Microfinance Institution management software

• Bonita Open Solution – Business Process Management

• Nexuiz – First-person shooter.
• OpenArena – First-person shooter.
• Red Eclipse – First-person shooter.
• Tremulous – First-person shooter.
• Unvanquished – First-person shooter.
• Xonotic – First-person shooter that runs on a heavily modified version of the Quake engine known as the DarkPlaces engine
• Warsow – First-person shooter fast-paced arena FPS game that runs on the Qfusion engine

• WINE – Allows Windows applications to be run on Unix-like operating systems

• ChessV
• Fairy-Max
• GNU Chess
• PyChess
• XBoard
• Lichess

• GCompris – software suite comprising educational entertainment software for children aged 2 to 10
• Tux, of Math Command
• Tux Paint

• MAME – Multi-platform emulator designed to recreate the hardware of arcade game systems
• MESS – Multi-platform emulator designed to recreate the hardware of video game consoles
• RetroArch – Cross-platform front-end for emulators, game engines and video games
• Snes9x – A Super Nintendo emulator
• Stella – Atari 2600 emulator
• PCSX – A PlayStation emulator designed to recreate the hardware of the original PlayStation system
• PCSX2 – A PlayStation 2 emulator designed to recreate the hardware of PlayStation 2 system
• PPSSPP – A PlayStation Portable emulator designed to recreate the hardware of PlayStation Portable system
• Project64 – A Nintendo 64 emulator
• RPCS3 – A PlayStation 3 emulator designed to recreate the hardware of PlayStation 3 system
• Dolphin (emulator) – A GameCube and Wii emulator designed to recreate the hardware of GameCube and Wii systems
• Citra (emulator) – A Nintendo 3DS and Wii emulator designed to recreate the hardware of Nintendo 3DS systems
• Cemu – A Wii U emulator designed to recreate the hardware of Wii U systems

• Frets on Fire

• UltraStar

• StepMania

• Pingus – Lemmings alternative with penguins instead of lemmings

• Luanti – An open source voxel game engine

• GLtron

• Endless Sky – Space trading and combat simulation
• FlightGear – Flight simulator

• OpenTTD – Business simulation game in which players try to earn money via transporting passengers and freight by road, rail, water and air
• SuperTuxKart – Kart racing game that features mascots of various open-source projects

• 0 A.D. – Real-time strategy video game
• Freeciv – Turn-based strategy game inspired by proprietary Sid Meier's Civilization series
• Glest
• The Battle for Wesnoth – Turn-based strategy video game with fantasy setting

• Gramps (software) – a free and open source genealogy software

• QGIS – cross-platform desktop geographic information system (GIS) application to view, edit, and analyse geospatial data

• Evergreen – Integrated Library System initially developed for the Georgia Public Library Service's PINES catalog
• Koha – SQL-based library management
• NewGenLib
• OpenBiblio
• PMB
• refbase – Web-based institutional repository and reference management software

• Darktable – Digital image workflow management, including RAW photo processing
• digiKam – Integrated photography toolkit including editing abilities
• GIMP – Raster graphics editor aimed at image retouching/editing
• Inkscape – Vector graphics editor
• Karbon – Scalable vector drawing application in KDE
• Krita – Digital painting, sketching and 2D animation application, with a variety of brush engines
• LazPaint – Lightweight raster and vector graphics editor, aimed at being simpler to use than GIMP
• LightZone – Free, open-source digital photo editor software application.
• RawTherapee – Digital image workflow management aimed at RAW photo processing

• OpenStreetMap – open geographic database updated and maintained by a community of volunteers via open collaboration.

• ALTRAN
• FriCAS
• GAP (computer algebra system)
• GiNaC
• gnuplot
• Maxima
• Mathomatic
• Normaliz
• SageMath
• Singular (software)
• SymPy
• Yacas

• Axiom
• Cadabra
• Cambridge Algebra System
• CPMP-Tools
• CoCoA
• Erable
• PARI/GP
• Reduce
• Xcas

• FORM (symbolic manipulation system)

• R – Statistics software

• Octave – Numerical analysis software
• Scilab – Numerical analysis software

• Geogebra – Geometry and algebra

• LibreOffice Calc – spreadsheet component of the LibreOffice package
• Gnumeric – spreadsheet program of the GNOME Project
• Calligra Sheets – spreadsheet component of the Calligra Suite in KDE
• Pyspread – spreadsheet which uses Python for macro programming, and allows each cell to contain data, the results of a calculation, a Python program, or the results of a Python program.

• Celestia (Android, iOS)
• Calligra (Android)
• Collabora Online Libre office for online collaboration and mobile devices. (Android)
• Conversations (Android)
• F-Droid (Android) – app store and software repository
• I2P (Android) – anonymous network layer (implemented as a mix network) that allows for censorship-resistant, peer-to-peer communication.
• Kiwix: Offline web browser that allows users to download the entire content of Wikipedia for offline learning purposes. (Android)
• Krita (Android)
• Linphone (Android, iOS)
• Maps.me (Android)
• Monal (iOS)
• NetHunter App Store (Android) – fork of F-Droid for Kali NetHunter
• OpenVPN (Android, iOS) – virtual private network (VPN) system that implements techniques to create secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities. It implements both client and server applications.
• Orbot (Android, iOS) – free proxy app that provides anonymity on the Internet for users of the Android and iOS operating systems. It allows traffic from apps such as web browsers, email clients, map programs, and others to be routed via the Tor network.
• Organic Maps (Android, iOS)
• OsmAnd (Android)
• Quicksy (Android)
• Stellarium (Android, iOS)
• Tor Browser – onion-routed browser by The Tor Project, based on Firefox ESR
• VLC (Android, iOS)
• Wikipedia (Android, iOS) – See also: List of Wikipedia mobile applications

• Audacity
• Ardour: Professional digital audio workstation
• LMMS: Digital audio workstation

• Brasero (software)
• cdrtools
• K3b
• X-CD-Roast

• Pencil2D – For animations
• SWFTools – For scripting

• Blender Game Engine – Discontinued 2019
• Godot – Application for the design of cross-platform video games
• MonoGame – C# framework
• Open3DEngine – Based on Amazon Lumberyard
• Stride – (prev. Xenko) 2D and 3D cross-platform game engine originally developed by Silicon Studio

• KnightCap
• Leela Chess Zero – Universal Chess Interface chess engine
• Stockfish – Universal Chess Interface chess engine

• Pencil2D – Simple 2D graphics and animation program
• Synfig – 2D vector graphics and timeline based animation
• TupiTube (formerly KTooN) – Application for the design and creation of animation
• OpenToonz – Part of a family of 2D animation software
• Krita – Digital painting, sketching and 2D animation application, with a variety of brush engines
• Blender – Computer graphics software, Blender's Grease Pencil tools allow for 2D animation within a full 3D pipeline.
• mtPaint – raster graphics editor for creating icons, pixel art

• Blender – Computer graphics software featuring modeling, sculpting, texturing, rigging, simulation, rendering, camera tracking, video editing, and compositing
• MakeHuman
• OpenFX – Modeling and animation software with a variety of built-in post processing effects
• Seamless3d – Node-driven 3D modeling software
• Wings 3D – subdivision modeler inspired by Nendo and Mirai from Izware.

• Shotwell

• Eye of GNOME
• F-spot
• feh
• Geeqie
• Gthumb
• Gwenview
• KPhotoAlbum
• Opticks

• GeoDa
• GeoServer
• GeoTools
• GRASS GIS
• GvSIG
• ILWIS
• JUMP GIS
• Kosmo (GIS)
• Libre Map Project
• MapWindow GIS
• Mapnik
• MapServer
• Marble
• OpenStreetMap
• OpenLayers
• PostGIS
• QGIS
• SAGA GIS
• uDig
• Whitebox Geospatial Analysis Tools

• Aegisub
• Gnome Subtitles
• Subtitle Composer (KDE)
• Subtitle Edit

• Dr. DivX
• FFmpeg
• MEncoder
• OggConvert

• Avidemux
• AviSynth
• Blender
• Cinelerra
• Flowblade
• Kdenlive
• Kino
• LiVES
• LosslessCut
• Natron
• Olive
• OpenShot
• Open Movie Editor
• Pitivi
• Shotcut
• VirtualDub
• VirtualDubMod
• VideoLAN Movie Creator

• DeVeDe
• DVD Flick
• DVDStyler

• Celtx – Media pre-production software
• Open Broadcaster Software (OBS) – Cross-platform streaming and recording program

• K9Copy
• Thoggen

• Avidemux
• HandBrake
• FFmpeg
• OggConvert

• Media Player Classic
• VLC media player
• mpv

• Revive Adserver

• Asterisk – Telephony and VoIP server
• Ekiga – Video conferencing application for GNOME and Microsoft Windows
• ConferenceXP – video conferencing application for Windows XP or later
• Dino - xmpp client, supporting both OMEMO encryption and Jingle Audio/Video protocol, under Windows, Linux and BSD.
• FreePBX – Front-end and advanced PBX configuration for Asterisk
• FreeSWITCH – Telephony platform
• Gajim – xmpp client
• I2P – anonymous network layer (implemented as a mix network) that allows for censorship-resistant, peer-to-peer communication.
• Jami – Cross-platform, peer to peer instant-messaging and video-calling protocol that offers end-to-end encryption and SIP client
• Jitsi – Java VoIP and Instant Messaging client
• QuteCom – Voice, video, and IM client application
• Enterprise Communications System sipXecs – SIP Communications Server
• Slrn – Newsreader
• Telegram
• Twinkle – VoIP softphone
• Tox – Cross-platform, peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption

• Amavis – Email content filter
• Claws Mail – Email Client
• Fetchmail – Email Retrieval
• Geary – Email client based on WebKitGTK+
• GNUMail – Cross-platform email client
• Hula – Discontinued mail and calendar project
• K-9 Mail – Android Email Client
• MailScanner – Email security system
• MH Message Handling System – Email Client
• Modest – Email Client
• Mozilla Mail & Newsgroups – Email Client that was part of the now discontinued Mozilla Application Suite
• Mozilla Thunderbird – Email, news, RSS, and chat client
• POPFile – Cross-platform mail filter
• Roundcube – Web-based IMAP email client
• Sylpheed – Email and News Client
• Sympa – MLA software
• Vpopmail – Email management software

FTP Open Source Software.

• Filezilla

Servidor

• GNU Queue
• HTCondor
• pexec

• Apache Axis2 – Web service framework (implementations are available in both Java & C)
• Apache Geronimo – Application server
• Bonita Open Solution – a J2EE web application and java BPMN2 compliant engine
• GlassFish – Application server
• Apache Tomcat – Servlet container and standalone webserver
• JBoss – Application server
• OpenRemote – IoT Middleware
• TAO (software) – C++ implementation of the OMG's CORBA standard
• Enduro/X – C/C++ middleware platform based on X/Open group's XATMI and XA standards

• Akregator – Platforms running KDE
• Liferea – Platforms running GNOME
• NetNewsWire – macOS, iOS
• RSS Bandit – Windows, using .NET framework
• RSSOwl – Windows, macOS, Solaris, Linux using Java SWT Eclipse
• Sage (Mozilla Firefox extension)

• I2P – anonymous network layer (implemented as a mix network) that allows for censorship-resistant, peer-to-peer communication.
• Popcorn Time – Multi-platform, free, and open-source media player
• qBittorrent – Alternative to popular clients such as μTorrent
• Transmission – BitTorrent client
• Deluge – BitTorrent client

• Drupal
• Liferay
• Sun Java System Portal Server
• uPortal

• FreeNX
• OpenVPN
• rdesktop
• Synergy
• VNC (RealVNC, TightVNC, UltraVNC)
• Remmina (based on FreeRDP)

• Chromium – web browser using the custom Blink engine from which Google Chrome draws its source code
• Brave – privacy-focused web browser based on Chromium browser
• Falkon – web browser based on Blink engine, a KDE project
• Firefox – Mozilla-developed web browser using Gecko layout engine
• Waterfox – Firefox fork supporting legacy extensions, 64-bit only
• Pale Moon – a customizable fork of Firefox
• Tor Browser – onion-routed browser by The Tor Project, based on Firefox ESR
• GNOME Web – WebKit-based web browser for the GNOME desktop environment
• Midori – Lightweight web browser using the WebKit layout engine
• qutebrowser – keyboard operated Webkit-based browser with vi-like keybindings
• SeaMonkey Navigator – the SeaMonkey internet suite's web browser
• Surf – a minimal tab-less browser by suckless.org using WebKitGTK
• Firefox Focus – privacy-focused mobile web browser from Mozilla available for Android and iOS

• Lynx – a text-based web browser developed since 1992
• Links – a text-based browser with a framebuffer-based graphical mode
• ELinks – fork of Links with JavaScript support

• Cheese – GNOME webcam application
• Guvcview – Linux webcam application

• cURL
• HTTrack
• Wget

• Apache Cocoon – A web application framework
• Apache – The most popular web server
• AWStats – Log file parser and analyzer
• BookmarkSync – Tool for browsers
• Caddy – an extensible, cross-platform, open-source web server written in Go.
• Cherokee – Fast, feature-rich HTTP server
• curl-loader – Powerful HTTP/HTTPS/FTP/FTPS loading and testing tool
• FileZilla – FTP
• Hiawatha – Secure, high performance, and easy-to-configure HTTP server
• HTTP File Server – User-friendly file server software, with a drag-and-drop interface
• lighttpd – Resource-sparing, but also fast and full-featured, HTTP Server
• Lucee – CFML application server
• Nginx – Lightweight, high performance web server/reverse proxy and e-mail (IMAP/POP3) proxy
• NetKernel – Internet application server
• Qcodo – PHP5 framework
• Squid – Web proxy cache
• Vaadin – Fast, Java-based framework for creating web applications
• Varnish – High-performance web application accelerator/reverse proxy and load balancer/HTTP router
• XAMPP – Package of web applications including Apache and MariaDB
• Zope – Web application server

• Searx – Self-hostable metasearch engine
• YaCy – P2P-based search engine

• JXplorer – LDAP client
• Nextcloud – A fork of ownCloud
• OpenLDAP – LDAP server
• ownCloud – File share and sync server
• Wireshark – Network monitor

• Apache OpenOffice – The cross platform office productivity suite from Apache Software Foundation (ASF) consists of programs for word processing, spreadsheets, presentation, diagrams and drawings, databases, etc.
• Calligra Suite – The office productivity suite from KDE consists of programs for word processing, spreadsheets, presentation, databases, vector graphics, and digital painting
• Collabora Online – Enterprise-ready edition of LibreOffice, web application, mobile phone, tablet, Chromebook and desktop (Windows, macOS, Linux)^[6]
• LibreOffice – The cross platform office productivity suite from The Document Foundation (TDF) consists of programs for word processing, spreadsheets, presentation, diagrams and drawings, databases, etc.
• OnlyOffice Desktop Editors – An open-source offline edition of the Cloud

Be advised that available distributions of these systems can contain, or offer to build and install, added software that is neither free software nor open-source.

• BSD: FreeBSD, OpenBSD, NetBSD, GhostBSD, TrueNAS, MidnightBSD, DragonFly BSD, OPNsense, pfSense, XigmaNAS, among others.
• GrapheneOS
• Kali NetHunter
• Linux: Debian, Ubuntu, Manjaro, Fedora, openSUSE, antiX, NixOS, Kali, Alpine, Tails, Mageia, Slackware, Gentoo, BlackArch, among others.
• LineageOS: An android-based operative system for tablets and mobile phones.
• GNU Hurd
• Mobian
• Plasma Mobile
• PostmarketOS
• PureOS
• Ubuntu Touch
• Redox OS

• AppleWin
• DOSBox – DOS programs emulator (including PC games)
• GNOME Boxes
• Hercules (emulator)
• Kernel-based Virtual Machine
• QEMU
• VirtualBox – hosted hypervisor for x86 virtualization

• Chandler – Developed by the Open Source Applications Foundation (OSAF)
• KAddressBook
• Kontact
• KOrganizer
• Mozilla Calendar – Mozilla-based, multi-platform calendar program
• Novell Evolution
• Perkeep – Personal data store for pictures
• Project.net – Commercial project management
• TeamLab – Platform for project management and collaboration

• Bugzilla
• Mantis
• Mindquarry
• Redmine
• Trac

• Bison
• CodeSynthesis XSD – XML Data Binding compiler for C++
• CodeSynthesis XSD/e – Validating XML parser/serializer and C++ XML Data Binding generator for mobile and embedded systems
• Flex lexical analyser – Generates lexical analyzers
• Open Scene Graph – 3D graphics application programming interface
• OpenSCDP – Open Smart Card Development Platform
• SableCC – Parser generator for Java and .NET
• SWIG – Simplified Wrapper and Interface Generator for several languages
• ^txt2regex$
• xmlbeansxx – XML Data Binding code generator for C++
• YAKINDU Statechart Tools – Statechart code generator for C++ and Java

• Doxygen – Tool for writing software reference documentation. The documentation is written within code
• Mkd – Extracts software documentation from source code files, pseudocode, or comments
• Natural Docs – Claims to use a more natural language as input from the comments, hence its name

• Autoconf
• Automake
• CMake

• GNU Debugger – A portable debugger that runs on many Unix-like systems
• Memtest86 – Stress-tests RAM on x86 machines
• Xnee – Record and replay tests

• Active Agenda – Operational risk management and Rapid application development platform

• Chemistry Development Kit
• JOELib
• OpenBabel

• Jupyter

• CellProfiler – Automatic microscopic analysis, aimed at individuals lacking training in computer vision
• Endrov – Java-based plugin architecture designed to analyse complex spatio-temporal image data
• Fiji – ImageJ-based image processing
• Ilastik – Image-classification and segmentation software
• ImageJ – Image processing application developed at the National Institutes of Health
• IMOD – 2D and 3D analysis of electron microscopy data
• ITK – Development framework used for creation of image segmentation and registration programs
• KNIME – Data analytics, reporting, and integration platform
• VTK – C++ toolkit for 3D computer graphics, image processing, and visualisation
• 3DSlicer – Medical image analysis and visualisation

• GROMACS – Protein, lipid, and nucleic acid simulation
• LAMMPS – Molecular dynamics software
• MDynaMix – General-purpose molecular dynamics, simulating mixtures of molecules
• ms2 – molecular dynamics and Monte Carlo simulation package to predict thermophysical properties of fluids
• NWChem – Quantum chemical and molecular dynamics software

• Avogadro – Plugin-extensible molecule visualisation
• BALLView – Molecular modeling and visualisation
• Jmol – 3D representation of molecules in many formats, for teaching use
• Molekel – Molecule viewing software
• MeshLab – Able to import PDB dataset and build up surfaces from them
• PyMOL – High-quality representations of small molecules and biological macromolecules
• QuteMol – Interactive molecule representations offering an array of innovative OpenGL visual effects
• RasMol – Visualizes biological macromolecules

• Ninithi – Visualise and analyse carbon allotropes, such as carbon nanotube, Fullerene, graphene nanoribbons

• Veusz

• CP2K – Atomistic and molecular simulation of solid-state, liquid, molecular, and biological systems

• recordMyDesktop

• BOINC
• Electric Sheep
• XScreenSaver

• List of free and open source simulation software

• R – Statistics software
• LimeSurvey – Online survey system

• Go Bible – A free Bible viewer application for Java mobile phones
• Marcion – Coptic–English/Czech dictionary
• OpenLP – A worship presentation program licensed under the GNU General Public License
• The SWORD Project – The CrossWire Bible Society's free software project

• Jitsi Meet
• OpenMeetings
• Conference XP
• Jami
• BigBlueButton

• Open-source software
• Open-source license
• Comparison of file synchronization software § Open-source
• List of HDL simulators § Free and open-source simulators
• List of optimization software § Free and open-source software
• List of concept- and mind-mapping software § Free and open-source
• List of spreadsheet software § Free and open-source software
• Comparison of FTP client software § Free and open-source software
• GNOME Core Applications
• List of GNU packages
• List of KDE applications
• List of formerly proprietary software
• List of Unix commands

• AlternativeTo
• CodePlex
• Free Software Directory
• Freecode
• Open Hub
• SourceForge

• Open Source Software Directory (OSSD), a collection of FOSS organized by target audience.
• List of open-source programs (LOOP) for Windows, maintained by the Ubuntu Documentation Project.
• The OSSwin Project, a list of free and open-source software for Windows
• Apache Project List
• Apache Projects Directory
• Software - GNU Project - Free Software Foundation
• Free Software Directory