- Open the Way 3D
- OpenLitterMap
- OPERATION DRACULA
- Operation Dracula X
- Operation Smoochy
- Operation wow HD
- OperationAntiVirus
- Opinion Game
- Oportuno Beyond Infinity Pills Game HD
- Opp Ball
- Optical Inquisitor 17+
- Optical Inquisitor Zero
- Oracle - Ask anything
- Orange
- Orange Bouncing Ball
- Orange Genius
- Orange HD
- Orange Juice Brick Breaker
- Orange Pen
- Orbit Riders
- Orbit Shots
- Orbit Strike
- Orbit | Ultimate Dance Music Remix Station
- OrbitR
- Orbits.io
- Orbitum
- Orbo's Escape
- Orbolo
- Bubble Pop: Balloon Shooter 3D
- Orbt XL
- Orbz
- Orc Warrior Army Siege 3D - Royal Navy dead air counter battle
- Orchid Growth
- Orcrest
- OrcrestLite
- Order In The Court!
- Ordne Die Bunten Bälle LT