Starts with the letter 'O'
- Octopus Chess. Featuring the Sorcerer Snake, the Ninja Pawn, the Wazir Knight, the Ferz Knight and the Octopus. By Charles Daniel.
- Odin's Rune Chess. With pieces that were inspired by rune images and meanings.... By Gary K. Gifford.
- Omega Chess. This preset for Omega Chess enforces the rules and spots check, checkmate, and stalemate. Author: Fergus Duniho.
- Omega Transplant. The Champion and Wizard from Omega Chess are transplanted to the board system and rules used for Birds and Ninjas. By Charles Daniel.
- Opulent Lemurian Shatranj. Joe Joyce's Shaman and Hero pieces are on a large board. By David Paulowich.
- Outback Chess. Play this game with new pieces on plus-shaped board. Winner of the 84-square contest! Author: Tony Quintanilla and Timothy R. Newton. Inventor: Timothy R. Newton.
|6 'Play by mail item' entries listed||6 'Large board' entries listed|
Total items listed: 6