The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Metalhead Software (Publisher) (1 member)
- Metroidvania (Genre) (1 member)
- MicroProse (Developer) (1 member)
- Micro Graphic Image (Developer) (1 member)
- Microphone type: Disabled (Config) (1 member)
- Microsoft Studios (Publisher) (1 member)
- Microïds (Developer) (2 members)
- Middle-Earth (Series) (1 member)
- Midnight City (Publisher) (2 members)
- Midway Austin (Developer) (1 member)
- Midway Games (Developer) (3 members)
- Midway Games (Publisher) (8 members)
- Midway Studios Los Angeles (Developer) (1 member)
- Midway Studios Newcastle (Developer) (1 member)
- Mighty Rocket Studio (Developer) (1 member)
- Milestone (Developer) (16 members)
- Milestone (Publisher) (6 members)
- Millennium Kitchen (Developer) (1 member)
- Minato Soft (Developer) (1 member)
- Minato Soft (Publisher) (1 member)