The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Surveillance (2 members)
- Survival (24 members)
- Sustainable (13 members)
- Symbols (2 members)
- Syndication (1 member)
- TCL (10 members)
- TV (2 members)
- Tablatures (1 member)
- Template:Lizenz für Bilder (0 members)
- Templates (6 members)
- Timothy Leary (13 members)
- Ting (106 members)
- Tips (1 member)
- ToDo (1 member)
- Trading (1 member)
- Travel (1 member)
- Twitter (1 member)
- UFO (3 members)
- UNIX (27 members)
- USA (5 members)