The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Missing genre parameter (Infobox) (35 members)
- Missing internal resolution parameter (Infobox) (2,052 members)
- Missing release date parameter (Infobox) (126 members)
- Missing release type parameter (Infobox) (51 members)
- Mobile Suit Gundam (Series) (13 members)
- Mojang Studios (Developer) (1 member)
- Mondo Productions (Developer) (1 member)
- MonkeyPaw Games (Publisher) (2 members)
- Monkey Bar Games (Developer) (5 members)
- Monkey Island (Series) (1 member)
- Monolith Productions (Developer) (6 members)
- Monopoly (Series) (1 member)
- Monster Hunter (Series) (2 members)
- Monumental Games (Developer) (2 members)
- Moonbite Games (Developer) (1 member)
- Moonbite Games (Publisher) (1 member)
- Moonbot Studios (Developer) (1 member)
- Mortal Kombat (Series) (4 members)
- Mossmouth (Developer) (1 member)
- Mossmouth (Publisher) (1 member)