The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- System Categories (2 members)
- System Cluster (2 members)
- Systems (111 members)
- T-shirts (4 members)
- T8A Gladiator Images (8 members)
- T8C Gladiator Images (20 members)
- TBF-4 Combat Knife images (1 member)
- Tachyon Cannon (3 members)
- Tal System (8 members)
- Talon Shrike images (4 members)
- Talon Weapon Systems (11 members)
- Talon images (56 members)
- Talon series (2 members)
- Tamsa System (3 members)
- Tanga System (4 members)
- Tangaroa (2 members)
- Tankers (1 member)
- Tanys images (1 member)
- Taranis System (9 members)
- Tarantula GT-870 Mark 1 images (1 member)
- Targeting Computers (0 members)
- Tarsus (9 members)
- Taser Pistol images (1 member)
- Tayac I (1 member)
- Tayac System (10 members)
- Tears of Fire images (1 member)
- Tehachapi (5 members)
- Tehachapi images (2 members)
- Telescopic sights (8 members)
- Telescopic sights:telescopic sight (1 member)
- Template documentation (257 members)
- Template invoked modules (23 members)
- Templates (35 members)
- Templates imported from Wikipedia (57 members)
- Templates using TemplateStyles (93 members)
- Tephra Homing Mine (1 member)
- Tephra Homing Mine images (1 member)
- Terra (planet) (3 members)
- Terra Gazette (0 members)
- Terra III images (3 members)
- Terra Mills (1 member)
- Terra System (17 members)
- Terra images (1 member)
- Terrapin Images (51 members)
- Terrestrial Rocky (95 members)
- Tevarin (1 member)
- Tevarin Characters (4 members)
- Th.us'ūng System (7 members)
- TheDamnShames Images (0 members)
- The Ark (1 member)