The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Community websites (2 members)
- Community websites/es (0 members)
- Community websites/fi (0 members)
- Community websites/fr (0 members)
- Community websites/pl (0 members)
- Community websites/pt-br (0 members)
- Community websites/ru (0 members)
- Companion Cube images (6 members)
- Company images (1 member)
- Core team members (18 members)
- Creative Commons files (40 members)
- Curiosity Core players (6 members)
- Custom Test Chambers (3 members)
- Danes (1 member)
- Dead end pages (0 members)
- Defective Turret voice files (190 members)
- Defective Turret voice files/de (175 members)
- Defective Turret voice files/es (175 members)
- Defective Turret voice files/fr (175 members)
- Defective Turret voice files/ru (192 members)
- Deprecated pages (0 members)
- Destroyed Aperture images (1 member)
- Developer commentary (4 members)
- Developer commentary/fi (1 member)
- Developer commentary/fr (1 member)
- Developer commentary/pt-br (1 member)
- Developer commentary/ru (1 member)
- Development (13 members)
- Development/cs (3 members)
- Development/da (3 members)
- Development/de (1 member)
- Development/es (4 members)
- Development/fi (10 members)
- Development/fr (9 members)
- Development/ko (4 members)
- Development/nl (2 members)
- Development/pl (5 members)
- Development/pt-br (11 members)
- Development/ru (11 members)
- Development/zh-hans (1 member)
- Development/zh-hant (1 member)
- Disambiguation (18 members)
- Disambiguation/fi (6 members)
- Disambiguation/fr (3 members)
- Disambiguation/pl (1 member)
- Disambiguation/pt-br (8 members)
- Disambiguation/ru (7 members)
- Documentation templates (3 members)
- Doug Rattmann Player (2 members)
- Doug Rattmann images (14 members)