The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Marvel vs. Capcom (Series) (4 members)
- Marvelous Entertainment (Publisher) (4 members)
- Marvelous Inc. (Publisher) (1 member)
- Marvelous USA (Publisher) (1 member)
- Mass Effect (Series) (3 members)
- Mass Media Games (Developer) (1 member)
- Mastertronic Group (Publisher) (1 member)
- Mastiff (Publisher) (3 members)
- Matt Hazard (Series) (2 members)
- Maximum Family Games (Publisher) (1 member)
- Maximum Games (Publisher) (1 member)
- Maximum SPURS threads (Config) (5 members)
- Medal of Honor (Series) (4 members)
- Media.Vision (Developer) (1 member)
- Media Factory (Developer) (1 member)
- Media Molecule (Developer) (4 members)
- Mega Man (Series) (2 members)
- Memories Off (Series) (2 members)
- MercurySteam (Developer) (4 members)
- Metal Gear (Series) (6 members)