The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Iron Galaxy (Publisher) (1 member)
- Iron Galaxy Studios (Developer) (3 members)
- Iron Man (Series) (2 members)
- Irrational Games (Developer) (2 members)
- Isopod Labs (Developer) (1 member)
- Ivent Games (Developer) (1 member)
- Ivent Games (Publisher) (1 member)
- JV Games (Developer) (1 member)
- JV Games (Publisher) (1 member)
- Jackbox Games (Developer) (2 members)
- Jackbox Games (Publisher) (2 members)
- James Bond (Series) (4 members)
- Japan (Release region) (778 members)
- Japan Studio (Developer) (17 members)
- Jellyvision Games (Developer) (1 member)
- Jikkyou Powerful Pro Yakyuu (Series) (7 members)
- JoJo's Bizarre Adventure (Series) (3 members)
- Joe Danger (Series) (2 members)
- Johnson-Voorsanger Productions (Developer) (2 members)
- JoyBits (Developer) (3 members)
- Joysound (Series) (1 member)
- Juice Games (Developer) (1 member)
- Just Add Water (Developer) (4 members)
- Just Dance (Series) (8 members)
- KMM Interactive Entertainment (Developer) (1 member)
- Kadokawa Games (Developer) (1 member)
- Kadokawa Games (Publisher) (3 members)
- Kaga Create (Developer) (1 member)
- Kaga Create (Publisher) (1 member)
- Kaiko (Developer) (1 member)
- Kalypso Media (Publisher) (5 members)
- Kamen Rider (Series) (5 members)
- Kane & Lynch (Series) (2 members)
- Kaos Studios (Developer) (1 member)
- Karaoke Revolution (Series) (3 members)
- Kart racing (Genre) (9 members)
- KatGames (Developer) (1 member)
- Keen Games (Developer) (1 member)
- Kemco (Publisher) (2 members)
- Kero Makura (Developer) (1 member)
- Kero Makura (Publisher) (1 member)
- Key (Developer) (3 members)
- Keystone Game Studio (Developer) (1 member)
- Killzone (Series) (3 members)
- King Art Games (Developer) (2 members)
- Kingdom Hearts (Series) (2 members)
- Klei Entertainment (Developer) (3 members)
- Klei Entertainment (Publisher) (1 member)
- Koch Media (Publisher) (4 members)
- Koei Canada (Developer) (1 member)