The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Spam blacklist (1 member)
- Sub-Etha (1 member)
- Tag des offenen Hackspace (3 members)
- Theoretical Computer Science (1 member)
- Todo (1 member)
- Toiletten (3 members)
- Toiletten WCs (1 member)
- Transcript Verlag (5 members)
- Users (1 member)
- VeganHack (2 members)
- Virtual Freitagsfoo (12 members)
- Workshop (83 members)
- Workstation (4 members)