The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Areas (25 members)
- Audio Logs (4 members)
- Audio logs (46 members)
- Candidates for deletion (0 members)
- Candidates for speedy deletion (0 members)
- Citation needed (0 members)
- Cleanup (0 members)
- Collectibles (67 members)
- Community (4 members)
- Copyright templates (12 members)
- Developers (1 member)
- Disambiguations (0 members)
- Documentation templates (3 members)
- Formatting templates (23 members)
- Front page sections (3 members)
- Gameplay (1 member)
- Guides (18 members)
- Images (4 members)
- Images needing improvement (0 members)
- Infobox templates (2 members)
- Legal notices (3 members)
- Maps (1 member)
- Media (1 member)
- Navigation templates (4 members)
- Notice templates (13 members)
- Obelisks (7 members)
- Pages to be merged (0 members)
- Pages to be moved (0 members)
- Pages with broken file links (1 member)
- Screenshots (49 members)
- Stubs (0 members)
- Template documentation (55 members)
- Templates (24 members)
- Templates with bad documentation (0 members)
- Templates with no documentation (0 members)
- The Witness (4 members)
- The Witness Wiki (10 members)
- User groups (12 members)
- Wiki maintenance (13 members)
- Wiki skin images (4 members)
- Windmill (7 members)