The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- ISquared Games (Developer) (1 member)
- ISquared Games (Publisher) (1 member)
- Id Software (Developer) (3 members)
- Idea Factory (Developer) (11 members)
- Idea Factory (Publisher) (5 members)
- Idol Minds (Developer) (3 members)
- Ignition Entertainment (Publisher) (7 members)
- Ignition Tokyo (Developer) (1 member)
- Ilusis Interactive Graphics (Developer) (1 member)
- Ilusis Interactive Graphics (Publisher) (1 member)
- Imageepoch (Developer) (1 member)
- Images (1 member)
- ImaginEngine (Developer) (1 member)
- Immersion Games (Developer) (2 members)
- InFamous (Series) (3 members)
- InFramez Technology (Developer) (1 member)
- InFramez Technology (Publisher) (1 member)
- InXile Entertainment (Developer) (2 members)
- InXile Entertainment (Publisher) (2 members)
- Incinerator Studios (Developer) (3 members)