| Name | CR | Type | Environment |
| Daemon, Adikodaemon | 18 | outsider (daemon, evil, extraplanar) | any |
| Damai | 1/2 | humanoid (damai) | any (Daimalko) |
| Damai, Damai Guardian | 12 | humanoid (damai) | any (Daimalko) |
| Death Cruiser | 14 | undead (incorporeal) | any |
| Defrex | 11 | animal | temperate forests and hills (Vesk-2) |
| Defrex, Defrex Juvenile | 7 | animal | temperate forests and hills (Vesk-2) |
| Deh-Nolo | 14 | aberration | any |
| Demon, Flashfire | 12 | outsider (chaotic, demon, evil, extraplanar) | any (Abyss) |
| Demon, Pluprex | 13 | outsider (chaotic, demon, evil, extraplanar) | any (Abyss) |
| Demon, Prexian Mutantspawn | 11 | outsider (chaotic, evil, extraplanar) | any (Abyss) |
| Dessamar, Dessamar Imago | 1 | humanoid (dessamar) | any (Koshoria) |
| Dessamar, Dessamar Theurgist | 6 | humanoid (dessamar) | any (Koshoria) |
| Devil, Endbringer Devil (Dhalochar) | 19 | outsider (devil, evil, extraplanar, lawful) | any (Hell) |
| Devil, Hacker (Lislaroth) | 10 | outsider (devil, evil, extraplanar, lawful) | any (Hell) |
| Devil, Imp | 2 | outsider (devil, evil, extraplanar, lawful) | any (Hell) |
| Devil, Warmonger Devil (Levaloch) | 7 | outsider (devil, evil, extraplanar, lawful) | any (Hell) |
| Diaspora Wyrm | 8 | magical beast (aquatic) | cold aquatic (Diaspora) |
| Diaspora Wyrm, Diaspora Wyrm Saga | 17 | magical beast (aquatic) | cold aquatic (Nisis) |
| Diatha | 1/2 | vermin | any land |
| Diatha, Diatha Elder | 5 | vermin | any land |
| Dimensional Shambler | 8 | outsider (chaotic, evil, extraplanar) | any |
| Dinosaur, Ceratopsid | 8 | animal | any |
| Dinosaur, Dromaeosaurid | 3 | animal | any |
| Dinosaur, Plesiosaur | 7 | animal | any water |
| Dinosaur, Pterosaur | 3 | animal | any |
| Dinosaur, Sauropod | 10 | animal | any |
| Dinosaur, Theropod | 9 | animal | any |
| Dinosaur, Thyreophoran | 6 | animal | any |
| Dirindi, Dirindi Dabulist | 13 | humanoid (dirindi) | any (Arkanen, Osoro) |
| Dirindi, Dirindi Monster Hunter | 4 | humanoid (dirindi) | any (Arkanen, Osoro) |
| Dormakhabu | 11 | aberration (gray) | any |
| Draelik | 2 | humanoid (draelik) | any (Great Shadar) |
| Dragon (Chromatic), Young Adult Blue Dragon | 11 | dragon (earth) | any |
| Dragon (Metallic), Adult Silver Dragon | 14 | dragon (cold) | any |
| Dragon (Outer), Old Void Dragon | 18 | dragon | any vacuum |
| Dragon (Starmetal), Mature Adult Horacalcum Dragon | 15 | dragon | any |
| Dragonkin | 9 | dragon | any (Triaxus) |
| Drake, Radiation Drake | 9 | dragon | any |
| Dreamer | 8 | aberration | any sky (Liavara) |
| Drift Leech | | magical beast | the Drift |
| Drift Mote | 1/2 | outsider (extraplanar) | the Drift |
| Drift Native, Drift Architech | 10 | outsider (extraplanar) | the Drift |
| Drift Native, Time Eater | 2 | outsider (extraplanar) | the Drift |
| Driftdead | 2 | undead (extraplanar) | any (the Drift) |
| Driftdead | 2 | undead (extraplanar) | any (the Drift) |
| Driftdead, Driftdead Amalgam | 13 | undead (extraplanar) | any (the Drift) |
| Driftlure | 14 | outsider (extraplanar) | any (the Drift) |
| Dromada | 1/2 | magical beast | any |
| Dromada, Dromada Vigilant | 5 | magical beast | any |
| Drow, Drow Enforcer | 1 | humanoid (elf) | any (Apostae) |
| Drow, Drow Noble Arms Dealer | 11 | humanoid (elf) | any (Apostae) |
| Dust Manta | 6 | magical beast | warm deserts |
| Dust Manta, Dust Manta Monarch | 12 | magical beast | warm deserts |
| Dycepskian, Reptoid Host | 6 | humanoid (dycepskian, reptoid, shapechanger) | any |