- O & X for Watch
- O & X: Noughts and Crosses
- O is for Obliteration
- о х мастер
- O X Multi
- O-ZONE - Protect the Earth
- Oak Island Treasure Hunt
- Occidental Heroes
- Занимают племени
- Ocean Wars
- Octav
- OctoHits
- Octopus Evolution
- Odd Color - Test Your Color Vision
- Odds Are for Messages
- Ode To Heroes
- OEGames Land Navigation
- Off-Road Transport Trailer
- Office Story
- Office Thief - Escape Puzzle
- Officer's Skat
- OffRoad Runway Construction 18
- OG Switch
- OGS Notify
- Oh! Edo Towns
- OH~! My Office - Boss Sim Game
- OH~! My Office - Boss Sim Game
- Oil Barron
- Нефтяной Магнат - Бесплатная Бизнес Игра Как Стать Миллионером Oil Capitalist
- Oil Tycoon 2: Idle Empire Game
- Нефтяной Магнат: cимулятор
- Oil Tycoon: Idle Empire Games
- Oil, Inc. - Idle Clicker
- Okey Arataş
- Okhlos: Sigma
- Old-School Snafu
- Olimpo vs Slimes
- Olympus Defense TD. Rising Gods башня обороны Война Боги арены
- Olympus Rising: Hero Defense
- Omar Sharif Bridge Card Game
- Omi Sri Lankan Card Game
- One Block Sudoku
- One Line - Игра-головоломка
- One Line Drawing - Duel
- One Night at Flumpty's
- One Night at Flumpty's 2
- One Night at Flumpty's 3
- Один путь - Нарисуйте точки
- One Plate!
- One Touch Line Draw Game
- OneBit Adventure
- PAOPAO классический - пао пао
- Onet Connect 2016
- Onet Connect Animal Legend
- OneUp: Tiger Edition
- Online Шашки LiveGames
- Шашки Online
- Online Шахматы LiveGames
- Online Преферанс LiveGames
- Online Zoo Builder
- Only Flaps And Horses
- Onmyoji
- Onmyoji Arena
- Opacha-mda
- Opdoku = Calcudoku + Mathdoku
- Все горит
- Operasyon ATAK
- Operasyon: ANKA
- Operation Ares - A Revolution on Mars! Recruit Spies, Complete Missions, & Gain Independence
- Operation Optics
- Operation: New Earth
- Optical Inquisitor 17+
- OptiFlight
- Orb Master
- Orbeez – O resgate dos Woozers
- Orbit defenders