Useful things and things whose name I often forget:

• Popups
• Help:Editing
• WP:STYLE
• WP:Copyrights
• WP:Fair use
• WP:V
• WP:RS
• WP:NOR
• WP:NPOV

Categories I'm (slowly) helping to clear:

• Category:Articles lacking sources (6,000 articles)
• Category:Articles with unsourced statements (6,000 articles)
• Category:Wikipedia references cleanup (52 48 5 articles! User:Bookofjude helped a lot more than I probably did.)
• Category:Cleanup by month (15,000 articles)