The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- THQ Digital Studios UK (Developer) (1 member)
- THQ Nordic (Publisher) (8 members)
- THQ San Diego (Developer) (1 member)
- THQ Studio Australia (Developer) (2 members)
- TREVA Entertainment (Publisher) (1 member)
- TSX instructions: Disabled (Config) (6 members)
- TT Fusion (Developer) (5 members)
- TT Games (Developer) (1 member)
- Tactical (Genre) (1 member)
- Tactical role-playing (Genre) (27 members)
- Taito (Developer) (3 members)
- Taito (Publisher) (1 member)
- Tales (Series) (6 members)
- Tales From Space (Series) (2 members)
- Tamsoft (Developer) (7 members)
- Tango Gameworks (Developer) (1 member)
- Targem Games (Developer) (5 members)
- Targem Games (Publisher) (2 members)
- Tarsier Studios (Developer) (1 member)
- TastyPlay (Developer) (1 member)
- Tate Multimedia (Developer) (1 member)
- Tate Multimedia (Publisher) (1 member)
- Team17 (Developer) (12 members)
- Team17 (Publisher) (9 members)
- Team6 Game Studios (Developer) (1 member)
- Team Bondi (Developer) (1 member)
- Team Ninja (Developer) (4 members)
- Team Shinobi (Developer) (2 members)
- Tears to Tiara (Series) (3 members)
- Techland (Developer) (7 members)
- Techland (Publisher) (2 members)
- Tecmo (Publisher) (2 members)
- Tecmo Koei (Publisher) (1 member)
- Teenage Mutant Ninja Turtles (Series) (4 members)
- Tekken (Series) (6 members)
- Televisa Home Entertainment (Publisher) (1 member)
- Telltale Games (Developer) (17 members)
- Telltale Games (Publisher) (16 members)
- Templates (22 members)
- Terminal Reality (Developer) (3 members)
- Terrible Posture Games (Developer) (1 member)
- Test Drive (Series) (2 members)
- Teyon (Developer) (4 members)
- Thatgamecompany (Developer) (6 members)
- The Adventure Company (Developer) (1 member)
- The Adventure Company (Publisher) (1 member)
- The Bearded Ladies Consulting (Developer) (1 member)
- The Behemoth (Developer) (1 member)
- The Bigs (Series) (2 members)
- The Darkness (Series) (2 members)