The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Old School Games (Developer) (2 members)
- Omega Force (Developer) (33 members)
- Omni Systems (Developer) (1 member)
- One Piece (Series) (4 members)
- One True Game Studios (Developer) (1 member)
- Ongakukan (Developer) (2 members)
- Ongakukan (Publisher) (2 members)
- Operation Flashpoint (Series) (2 members)
- Orange Juice (Developer) (1 member)
- Other Ocean Interactive (Developer) (3 members)
- Output scaling: FidelityFX Super Resolution (FSR) (Config) (1 member)
- Over The Top Games (Developer) (1 member)
- Overkill Software (Developer) (2 members)
- PAN Vision (Publisher) (1 member)
- PGA Tour (Series) (8 members)
- PPU LLVM Java mode handling: False (Config) (0 members)
- PPU LLVM Java mode handling: True (Config) (0 members)
- PPU LLVM accurate vector NaNs: On (Config) (1 member)
- PPU decoder: Interpreter (static) (Config) (15 members)
- PPU thread count: 1 (Config) (1 member)
- PQube (Publisher) (7 members)
- PSN status: Disconnected (Config) (1 member)
- PSN status: RPCN (Config) (5 members)
- PSN status: Simulated (Config) (3 members)
- PSR Outdoors (Developer) (2 members)
- PSR Outdoors (Publisher) (2 members)
- Pac-Man (Series) (3 members)
- PachiPara (Series) (3 members)
- Pachinko (Genre) (14 members)
- Page 44 Studios (Developer) (1 member)
- Pages using duplicate arguments in template calls (15 members)
- Pages using vgregion with named parameters (1 member)
- Pages with broken file links (1 member)
- Pages with too many expensive parser function calls (0 members)
- Pandemic Studios (Developer) (3 members)
- Paon Corporation (Developer) (1 member)
- Paon Corporation (Publisher) (1 member)
- Papaya Studio (Developer) (2 members)
- Paradigm Entertainment (Developer) (1 member)
- Paradox Interactive (Publisher) (2 members)
- Paramount Digital Entertainment (Publisher) (4 members)
- Party (Genre) (24 members)
- Patches available (237 members)
- Payday (Series) (2 members)
- Pelfast (Developer) (1 member)
- Pelfast (Publisher) (1 member)
- People Can Fly (Developer) (1 member)
- Persona (Series) (3 members)
- Phoenix Studio (Developer) (1 member)
- Pi Studios (Developer) (1 member)
- Piacci (Publisher) (1 member)
- Pieces Interactive (Developer) (2 members)
- Pinball (Genre) (7 members)
- Pipeworks Software (Developer) (6 members)
- Pipeworks Studios (Developer) (1 member)
- Piranha Bytes (Developer) (1 member)
- Piranha Games (Developer) (1 member)
- Pivotal Games (Developer) (1 member)
- PixelJunk (Series) (8 members)
- Pixel Tales (Developer) (1 member)
- Pixelnest Studio (Developer) (1 member)
- Pixelopus (Developer) (1 member)
- Pixolane (Developer) (1 member)
- Pixolane (Publisher) (1 member)
- Plants vs. Zombies (Series) (1 member)
- Plastic (Developer) (2 members)
- Platform (Genre) (168 members)
- Platine Dispositif (Developer) (1 member)
- PlatinumGames (Developer) (7 members)
- PlayStation 3 exclusive (Release type) (304 members)
- PlayStation exclusive (Release type) (186 members)
- Playbrains (Developer) (2 members)
- Playdead (Developer) (1 member)
- Playdead (Publisher) (1 member)
- Playlogic Entertainment (Developer) (4 members)
- Playlogic Entertainment (Publisher) (1 member)
- Playlogic Game Factory (Developer) (1 member)
- Playlogic International (Publisher) (1 member)
- Playrix Entertainment (Developer) (1 member)
- Plug In Digital (Publisher) (1 member)
- Plunge Interactive (Developer) (1 member)
- Point-and-click (Genre) (13 members)
- Point of View (Developer) (1 member)
- Polyphony Digital (Developer) (5 members)
- Polytron Corporation (Developer) (1 member)
- PomPom Games (Developer) (1 member)
- PomPom Software (Developer) (1 member)
- PomPom Software (Publisher) (1 member)
- PopCap Games (Developer) (7 members)
- PopCap Games (Publisher) (5 members)
- Power Pros Production (Developer) (10 members)
- Power and Magic Development (Developer) (1 member)
- Preferred SPU threads (Config) (6 members)
- Premium Agency (Developer) (1 member)
- Press Play (Developer) (1 member)
- Press Play (Publisher) (1 member)
- Prince of Persia (Series) (4 members)
- Pro Evolution Soccer (Series) (11 members)
- Professional Baseball Spirits (Series) (9 members)
- Project Aces (Developer) (2 members)