The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Tactile Games ApS (3 members)
- Tapwave, Inc. (2 members)
- Team17 Digital Limited (1 member)
- TeamTO (3 members)
- Tec Toy Industria de Brinquedos S.A. (1 member)
- Templates (1 member)
- Tengen (1 member)
- The Pokemon Company (1 member)
- Tiger (1 member)
- Tiger Electronics (1 member)
- Title (411 members)
- Tony Hawk's (1 member)
- Treyarch (2 members)
- True Axis Pty. Ltd. (3 members)
- Tum Yeto (1 member)
- Tvos (3 members)
- UEP Systems (1 member)
- UGO Networks Inc (1 member)
- UGO Networks Inc. (1 member)
- US Gold Ltd (4 members)
- Ubisoft (7 members)
- Ubisoft Entertainment (1 member)
- Ultra (1 member)
- Unk (1 member)
- Unknown (9 members)
- Unreleased (2 members)
- VDO Games (1 member)
- Vicarious Visions (3 members)
- Vita (5 members)
- WayForward Technologies, Inc. (1 member)
- Web (15 members)
- Web Magistrates (1 member)
- Wii (12 members)
- Wiiu (1 member)
- Wiki Maintenance (1 member)
- Win (55 members)
- Windows Mobile (2 members)
- Wisdom Tree (1 member)
- WizardWorks Group, Inc. (1 member)
- X360 (11 members)
- Xbone (8 members)
- Xbox (10 members)
- Xplorys (1 member)
- ZX Spectrum (7 members)
- Zepplin Games (1 member)
- Zodiac (2 members)
- Zoo Games, Inc. (1 member)
- Zplay (Beijing) Info. Tech. Co., Ltd. (3 members)
- Zune (1 member)
- Zxspectrum (7 members)