The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Achievements/ja (3 members)
- Achievements/ko (3 members)
- Achievements/pl (1 member)
- Achievements/pt-br (1 member)
- Achievements/ru (4 members)
- Achievements/zh-hant (2 members)
- Adventure Core players (2 members)
- Adventure Core voice files/es (59 members)
- Adventure core voice files (59 members)
- Adventure core voice files/de (59 members)
- Adventure core voice files/fr (59 members)
- Adventure core voice files/ru (60 members)
- Americans (15 members)
- Anger Core players (0 members)
- Announcer voice files (95 members)
- Announcer voice files/de (95 members)
- Announcer voice files/es (95 members)
- Announcer voice files/fr (95 members)
- Announcer voice files/ru (132 members)
- Aperture Desk Job (1 member)
- Aperture Desk Job images (12 members)
- Aperture Hand Lab images (6 members)
- Aperture Science Employees (37 members)
- Aperture Tag: The Paint Gun Testing Initiative images (33 members)
- Apparel images (9 members)
- Arnhem (1 member)
- Article with commented explanation requests (0 members)
- Article with uncommented explanation requests (2 members)
- Articles marked for cleanup (18 members)
- Articles marked for cleanup/lang (4 members)
- Articles marked for grammar correction (1 member)
- Articles marked for grammar correction/lang (0 members)
- Articles marked for open review (2 members)
- Articles needing copy-editing (0 members)
- Articles needing images (98 members)
- Articles needing videos (7 members)
- Articles needing walkthrough (2 members)
- Articles that read like advertisements (1 member)
- Artwork images (444 members)
- Artwork images/fi (2 members)
- Artwork images/pt-br (3 members)
- Artwork images/ru (2 members)
- Atlas images (35 members)
- Audio (5 members)
- Audio/cs (2 members)
- Audio/da (1 member)
- Audio/de (3 members)
- Audio/es (4 members)
- Audio/fi (2 members)
- Audio/fr (7 members)