| Name | Map Tool Token Link | Type |
|---|---|---|
| Ocean Strider | RPTok | Fey |
| Octopus | RPTok | Animal |
| Giant Octopus | RPTok | Animal |
| Ogre | |
Giant |
| 4th-Level Barbarian Ogre | RPTok | Giant |
| Ogre Mage | |
Giant |
| Black Pudding | |
Ooze |
| Elder Black Pudding | |
Ooze |
| Gelatinous Cube | |
Ooze |
| Gray Ooze | |
Ooze |
| Ochre Jelly | |
Ooze |
| 1st-Level Warrior Orc | RPTok | Humanoid |
| Orcwort | RPTok | Plant |
| Wortling | RPTok | Plant |
| Ormyrr | RPTok | Monstrous Humanoid |
| Otyugh | |
Aberration |
| Owl | RPTok | Animal |
| Giant Owl | RPTok | Magical Beast |
| Owlbear | |
Magical Beast |