The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Transmission Games (Developer) (2 members)
- Trapdoor (Developer) (1 member)
- Trapdoor (Publisher) (1 member)
- Traveller's Tales (Developer) (16 members)
- Treasure Co. (Developer) (1 member)
- Trendy Entertainment (Developer) (1 member)
- Treyarch (Developer) (8 members)
- Tri-Ace (Developer) (4 members)
- Tri-Crescendo (Developer) (2 members)
- Trickstar Games (Developer) (3 members)
- Trine (Series) (2 members)
- Trine Games (Developer) (3 members)
- Trion Worlds (Developer) (1 member)
- Trion Worlds (Publisher) (1 member)
- Triumph Studios (Developer) (1 member)
- Trivia (Genre) (26 members)
- Tru Blu Entertainment (Publisher) (9 members)
- Turn-based (Genre) (1 member)
- Turn-based tactics (Genre) (4 members)
- Two Tribes (Developer) (1 member)
- UFC Undisputed (Series) (3 members)
- UFO Interactive Games (Publisher) (3 members)
- UIG Entertainment (Publisher) (1 member)
- UNKNOWN GAMES (Developer) (2 members)
- Ubisoft (Developer) (10 members)
- Ubisoft (Publisher) (101 members)
- Ubisoft Blue Byte (Developer) (1 member)
- Ubisoft Bucharest (Developer) (4 members)
- Ubisoft Milan (Developer) (3 members)
- Ubisoft Montpellier (Developer) (5 members)
- Ubisoft Montreal (Developer) (23 members)
- Ubisoft Paris (Developer) (2 members)
- Ubisoft Pune (Developer) (1 member)
- Ubisoft Quebec (Developer) (2 members)
- Ubisoft Reflections (Developer) (1 member)
- Ubisoft San Francisco (Developer) (2 members)
- Ubisoft Shanghai (Developer) (8 members)
- Ubisoft Singapore (Developer) (1 member)
- Ubisoft Sofia (Developer) (3 members)
- Ubisoft Toronto (Developer) (1 member)
- Ubisoft Vancouver (Developer) (1 member)
- Ultraman (Series) (1 member)
- Umineko no Naku Koro ni (Series) (2 members)
- Uncharted (Series) (3 members)
- Underground Development (Developer) (2 members)
- United Front Games (Developer) (3 members)
- United Game Artists (Developer) (1 member)
- Unknown/invalid (Release region) (0 members)
- Upper One Games (Developer) (1 member)
- Us! (Developer) (1 member)