The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Agencies (0 members)
- Auxiliary templates (7 members)
- Buildings (10 members)
- Candidates for deletion (1 member)
- Candidates for speedy deletion (0 members)
- Citation needed (0 members)
- Cleanup (4 members)
- Colonists (0 members)
- Community (5 members)
- Copyright templates (10 members)
- Decorations (11 members)
- Disambiguations (0 members)
- Documentation templates (51 members)
- Dome Services (8 members)
- Domes (6 members)
- Drones (0 members)
- ES translation (4 members)
- Editcopies (7 members)
- Encyclopedia images (114 members)
- Formatting templates (43 members)
- Front page sections (4 members)
- General wiki templates (1 member)
- Hidden categories (13 members)
- Homes, Education & Research (16 members)
- Icons (184 members)
- Image and media templates (1 member)
- Images (18 members)
- Images needing improvement (0 members)
- Indexed pages (0 members)
- Infobox templates (3 members)
- Infrastructure (15 members)
- Legal notices (3 members)
- Life Support (9 members)
- Mars (1 member)
- Media (2 members)
- Meta templates (2 members)
- Mysteries of Mars (10 members)
- Navbox templates (1 member)
- Navigation templates (3 members)
- Noindexed pages (0 members)
- Notice templates (15 members)
- Pages containing omitted template arguments (0 members)
- Pages to be merged (0 members)
- Pages to be moved (0 members)
- Pages using duplicate arguments in template calls (0 members)
- Pages using invalid self-closed HTML tags (0 members)
- Pages where expansion depth is exceeded (0 members)
- Pages where node count is exceeded (0 members)
- Pages where template include size is exceeded (0 members)
- Pages with broken file links (5 members)