The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Basics (3 members)
- Candidates for deletion (1 member)
- Candidates for speedy deletion (0 members)
- Citation needed (0 members)
- Cleanup (0 members)
- Collisions (7 members)
- Community (3 members)
- Composition (5 members)
- Copyright templates (12 members)
- Developers (1 member)
- Disambiguations (0 members)
- Documentation templates (3 members)
- Formatting templates (22 members)
- Front page sections (0 members)
- Galaxies (18 members)
- Gravity (5 members)
- Heating (32 members)
- Hidden categories (0 members)
- Images (3 members)
- Images needing improvement (0 members)
- Infobox templates (1 member)
- Legal notices (3 members)
- Logos (1 member)
- Material Composition (0 members)
- Media (2 members)
- Navigation templates (3 members)
- Notice templates (15 members)
- Orbital Mechanics (13 members)
- Pages to be merged (0 members)
- Pages to be moved (0 members)
- Pages with broken file links (0 members)
- Physics (60 members)
- Planets (1 member)
- Screenshots (21 members)
- Simulation (34 members)
- Stars (8 members)
- Stubs (28 members)
- Surface (33 members)
- Template documentation (49 members)
- Templates (16 members)
- Templates with bad documentation (0 members)
- Templates with no documentation (0 members)
- Unattributed files (0 members)
- Universe Sandbox (2 members)
- Universe Sandbox 2 Wiki (0 members)
- Universe Sandbox Wiki (11 members)
- User groups (13 members)
- Videos (0 members)
- Wiki maintenance (14 members)
- Wiki skin images (3 members)