| Settings | |||||
|---|---|---|---|---|---|
| Name | Owner | Posts | Characters | ||
| Oldoria | Iarwain | 1 | 4 | ||
| Old Republic | Diaeresis | 16 | 19 | ||
| Olympus | Hellevi | 0 | 11 | ||
| omega-C | Neva | 1 | 5 | ||
| Omegaverse | AndaisQ | 0 | 1 | ||
| Ommatidium | decembercat | 0 | 2 | ||
| Omniscience | red | 1 | 5 | ||
| One Piece | Anya | 0 | 3 | ||
| Optophobia | root | 0 | 3 | ||
| Orbital Deck | Evenstar | 0 | 2 | ||
| Orchid War Reborn | Sage/Nemesis | 0 | 0 | ||
| Order of the Stick | perinoveau | 4 | 29 | ||
| Original | Anya | 0 | 0 | ||
| Original Setting | Kappa | 1 | 1 | ||
| Ormulum | Orm | 3 | 6 | ||
| orphan black | ChaosMagic | 0 | 1 | ||
| Orrery of Worlds | Jarn | 0 | 0 | ||
| osirion | lintamande | 4 | 6 | ||
| Ossis | rusalkii | 0 | 2 | ||
| OTC | Evenstar | 8 | 12 | ||
| Otherverse | Zmavli | 0 | 2 | ||
| Otherways | Sage/Nemesis | 0 | 15 | ||
| otherwoods | aurelia | 0 | 1 | ||
| Otherworlds | Sage/Nemesis | 0 | 4 | ||
| Ouroboros | Anya | 0 | 5 | ||