| Name | CR | MR | Type | Environment |
| Gargoyle | 5 | 2 | monstrous humanoid (earth, mythic) | any |
| Giant, Fire Giant | 12 | 5 | humanoid (fire, giant, mythic) | warm mountains |
| Giant, Hill Giant | 9 | 3 | humanoid (giant, mythic) | temperate hills |
| Glaistig | 21 | 10 | fey (earth, mythic) | temperate forests or swamps |
| Golem, Flesh Golem | 9 | 3 | construct (mythic) | any |
| Graeae | 5 | 2 | monstrous humanoid (evil, mythic) | any |
| Greater Barghest | 8 | 2 | outsider (evil, extraplanar, lawful, mythic, shapechanger) | any |
| Grendel | 19 | 7 | monstrous humanoid (mythic) | cold swamps |
| Griffon | 5 | 2 | magical beast (mythic) | temperate hills |
| Grogrisant | 16 | 6 | magical beast (mythic) | temperate or warm plains or hills |
| Guardian Dragon | 24 | 10 | dragon (aquatic, mythic) | any |