The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Tyler Design and Tech (12 members)
- Typing-aid templates (12 members)
- Tyrol System (15 members)
- Tyrol V (1 member)
- Tyrol V images (1 member)
- UEE (83 members)
- UEEN Bengal-class vessels (5 members)
- UEEN Carrack-class vessels (2 members)
- UEEN Characters (1 member)
- UEEN Hammerhead-class vessels (18 members)
- UEEN Idris-class vessels (4 members)
- UEEN Javelin-class vessels (5 members)
- UEEN Nautilus-class vessels (1 member)
- UEEN Pegasus-class vessels (1 member)
- UEEN Perseus-class vessels (2 members)
- UEEN Polaris-class vessels (1 member)
- UEEN Retribution-class vessels (1 member)
- UEEN Ship Class Designations (11 members)
- UEEN Squadrons (16 members)
- UEEN vessels (16 members)
- UEEN vessels of unknown class (28 members)
- UEES War Hammer images (15 members)
- UEE (Squadron 42) Faction Characters (1 member)
- UEE Army Characters (2 members)
- UEE Characters (1 member)
- UEE Faction Characters (149 members)
- UEE Navy (7 members)
- UEE Navy Characters (48 members)
- UEE Senate Subcommittees (7 members)
- UEE Systems (39 members)
- UI (1 member)
- UPEN Perseus-class vessels (2 members)
- UPEN vessels (6 members)
- UPEN vessels of unknown class (3 members)
- UPE Faction Characters (5 members)
- UPE Navy Characters (1 member)
- USAF (1 member)
- UTV images (1 member)
- UltiFlex (2 members)
- Unclaimed (0 members)
- Unclaimed Systems (13 members)
- Under-construction templates (0 members)
- Underbarrel attachments (3 members)
- Underground bunker images (16 members)
- Underground bunkers (1 member)
- Undersuit images (31 members)
- Undersuits (27 members)
- Unguided bombs (2 members)
- Unisex clothing (3 members)
- United Empire of Earth (1 member)