The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Achievement images (3 members)
- Achievements (5 members)
- Candidates for deletion (0 members)
- Candidates for speedy deletion (0 members)
- Citation needed (0 members)
- Cleanup (0 members)
- Community (5 members)
- Concept art (1 member)
- Copyright templates (10 members)
- Disambiguations (0 members)
- Documentation templates (49 members)
- Formatting templates (21 members)
- General wiki templates (1 member)
- Help (7 members)
- Horizon (21 members)
- Horizon Wiki (9 members)
- Images (13 members)
- Images needing improvement (0 members)
- Infobox templates (2 members)
- Legal notices (3 members)
- Media (2 members)
- Modding (4 members)
- Notice templates (13 members)
- Pages to be merged (0 members)
- Pages to be moved (0 members)
- Pages with a poll (0 members)
- Pages with broken file links (2 members)
- Races (11 members)
- Research (8 members)
- Screenshots (28 members)
- Ships (1 member)
- Stubs (28 members)
- Templates (18 members)
- Templates with bad documentation (0 members)
- Templates with no documentation (0 members)
- User groups (5 members)
- User images (1 member)
- Videos (2 members)
- Wallpaper (1 member)
- Wiki maintenance (14 members)
- Wiki skin images (7 members)