The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Co-op (Game mode) (368 members)
- Code Mystics (Developer) (1 member)
- Codeglue (Developer) (1 member)
- Codemasters (Developer) (17 members)
- Codemasters (Publisher) (27 members)
- Coffee Stain Studios (Developer) (2 members)
- Cohort Studios (Developer) (6 members)
- ColdWood Interactive (Developer) (3 members)
- Cold Beam Games (Developer) (1 member)
- Cold Beam Games (Publisher) (1 member)
- Combat flight simulator (Genre) (22 members)
- Comcept (Developer) (1 member)
- Command & Conquer (Series) (2 members)
- Compile Heart, Red Entertainment (Publisher) (1 member)
- Compile Heart (Developer) (10 members)
- Compile Heart (Publisher) (12 members)
- Compulsion Games (Developer) (1 member)
- Configurations (79 members)
- Console exclusive (Release type) (550 members)
- Corecell Technology (Developer) (2 members)
- Coreplay (Developer) (1 member)
- Coresoft (Developer) (1 member)
- Costume Quest (Series) (2 members)
- Covers (822 members)
- Crafts & Meister (Developer) (3 members)
- Crash Time (Series) (2 members)
- Crave Entertainment (Publisher) (4 members)
- Creat Studios (Developer) (16 members)
- Creat Studios (Publisher) (10 members)
- Creative Assembly (Developer) (4 members)
- Creative Vault Studios (Developer) (1 member)
- Crispy's! (Developer) (1 member)
- Crispy's (Developer) (1 member)
- Criterion Games (Developer) (4 members)
- Crocodile Entertainment (Developer) (1 member)
- Crocodile Entertainment (Publisher) (1 member)
- Croteam (Developer) (1 member)
- Crunching Koalas (Developer) (1 member)
- Crypton (Developer) (5 members)
- Crysis (Series) (3 members)
- Crystal Dynamics (Developer) (3 members)
- Crytek (Developer) (4 members)
- Curve Digital (Publisher) (6 members)
- Curve Studios (Developer) (4 members)
- Curve Studios (Publisher) (5 members)
- Custom servers (Netplay) (34 members)
- Cyanide Studio (Developer) (7 members)
- CyberConnect2 (Developer) (10 members)
- CyberFront (Developer) (1 member)
- CyberFront (Publisher) (8 members)