| Name | CR | Type | Environment |
| Hadhayosh | 18 | magical beast (fire) | warm hills and deserts |
| Hag Eye Ooze | 3 | ooze
| temperate marshes or underground
|
| Hag Eye Ooze | 3 | ooze | temperate marshes or underground |
| Hag Eye Ooze, Coven Ooze | 9 | ooze
| temperate marshes or underground
|
| Hag, Annis Hag | 6 | monstrous humanoid | cold marshes |
| Hag, Ash Hag | 5 | monstrous humanoid | any urban or ruins |
| Hag, Blood Hag | 8 | monstrous humanoid (shapechanger) | any land |
| Hag, Dreamthief Hag | 11 | outsider (evil, extraplanar) | any (Dimension of Dreams) |
| Hag, Green Hag | 5 | monstrous humanoid | temperate marshes |
| Hag, Moon Hag | 7 | monstrous humanoid (extraplanar) | any (Boneyard) |
| Hag, Mute Hag | 11 | monstrous humanoid (cold) | cold plains, forests, and marshes |
| Hag, Night Hag | 9 | outsider (evil, extraplanar) | any evil-aligned plane |
| Hag, Sea Hag | 4 | monstrous humanoid (aquatic) | any aquatic |
| Hag, Storm Hag | 7 | monstrous humanoid | any temperate |
| Hag, Winter Hag | 7 | monstrous humanoid (cold) | cold forests or plains |
| Half-Celestial (Unicorn) | 4 | outsider (native) | temperate forests |
| Half-Dragon (Black Dragon, Basilisk) | 7 | dragon | temperate swamp or underground |
| Half-Fiend (Minotaur) | 6 | outsider (native) | temperate ruins or underground |
| Hallowed Lynx | 17 | magical beast | any |
| Hamadryad | 15 | fey | temperate forests |
| Hangman Tree | 7 | plant | temperate forests |
| Hanshepsu | 10 | construct | warm deserts (Osirion) |
| Harionago | 11 | undead | any land |
| Harpy | 4 | monstrous humanoid | temperate marshes |
| Harridan | 12 | magical beast | any mountain or desert |
| Haunted Construct Scarecrow | 5 | construct | any |
| Havero | 24 | aberration | any (outer space) |
| Havero | 24 | aberration | any (usually outer space) |
| Havero, Havero Tentacle | 6 | aberration | — |
| Heart Thief | 9 | outsider (chaotic, evil, native) | any forest |
| Heartrot Tree | 13 | plant | any forest or underground |
| Heikegani | 4 | aberration (aquatic) | any coastlines |
| Hell Engine Adamantine Golem | 20 | construct | any (Hell) |
| Hell Hound | 3 | outsider (evil, extraplanar, fire, lawful) | any (Hell) |
| Hell Hound, Nessian Warhound | 9 | outsider (evil, extraplanar, fire, lawful) | any (Hell) |
| Hellcat | 7 | outsider (evil, extraplanar, lawful) | any land (Hell) |
| Hellfire Ignis | 3 | fey (fire) | any forests or plains |
| Hellwasp Swarm | 8 | vermin (extraplanar, swarm) | any (Hell) |
| Herald, Arcanotheign | 15 | outsider (herald, incorporeal) | any (Maelstrom) |
| Herald, Basileus | 15 | outsider (devil, evil, extraplanar, herald, lawful) | any (Hell) |
| Herald, End's Voice | 15 | outsider (chaotic, extraplanar) | any (Astral Plane or Pharasma’s Boneyard) |
| Herald, Gravedragger | 15 | outsider (evil, heraldISG) | any (Abaddon or Astral Plane) |
| Herald, Great Elder Iuu | 15 | outsider (evil, giant, heraldISG, lawful) | temperate mountains (Hell) |
| Herald, Hand of the Inheritor | 15 | outsider (angel, extraplanar, good, herald, lawful) | any (Heaven) |
| Herald, Latten Mechanism | 15 | construct (extraplanar, heraldISG) | any (Axis) |
| Herald, Lawgiver | 15 | construct (extraplanar, herald, lawful) | any land (Axis) |
| Herald, Lawgiver | 15 | construct (extraplanar) | any |
| Herald, Mother’s Maw | 15 | undead (evil, extraplanar, herald) | any (Abaddon) |
| Herald, Mother's Maw | 15 | undead (evil, extraplanar) | — |
| Herald, Night Monarch | 15 | outsider (chaotic, extraplanar, good) | any |
| Herald, Night Monarch | 15 | outsider (chaotic, extraplanar, good, herald) | any (Elysium) |
| Herald, Personification of Fury | 15 | outsider (air, elemental, extraplanar, herald, water) | any air or water (Plane of Air or Plane of Water) |
| Herald, Steward of the Skein | 15 | outsider (extraplanar, herald, psychopomp, shapechanger) | any (Boneyard) |
| Herald, Sunlord Thalachos | 15 | outsider (angel, extraplanar, good, herald, shapechanger) | any (extraplanar) |
| Herald, Tarrasque | 25 | magical beast (spawn of Rovagug [see page 275]) | any |
| Herald, Thais | 15 | outsider (chaotic, extraplanar, good, herald, shapechanger) | any (Elysium) |
| Herald, The First Blade | 15 | outsider (chaotic, extraplanar, herald) | any (Elysium) |
| Herald, The Grand Defender | 15 | construct (extraplanar, herald) | any land (Heaven) |
| Herald, The Grim White Stag | 15 | outsider (extraplanar, good, lawful) | any land (Heaven) |
| Herald, The Menotherian | 15 | outsider (chaotic, extraplanar, herald, shapechanger) | any (Elysium) |
| Herald, The Old Man | 15 | outsider (extraplanar, herald, lawful) | any land (Axis) |
| Herald, The Prince in Chains | 15 | outsider (evil, extraplanar, kyton, lawful) | any (Plane of Shadow) |
| Herald, The Prince in Chains | 15 | outsider (evil, extraplanar, lawful) | any |
| Herald, The Spirit of Adoration | 15 | outsider (extraplanar, good, herald, shapechanger) | any (Nirvana) |
| Herald, The Stabbing Beast | 15 | outsider (evil, extraplanar, herald, shapechanger) | any land (Axis) |
| Herald, Yethazmari | 15 | outsider (chaotic, evil, extraplanar, herald) | any (Abyss) |
| Herald, Yethazmari | 15 | outsider (chaotic, extraplanar, evil) | any |
| Herd Animal, Antelope | 1/2 | animal | temperate or warm plains |
| Herd Animal, Aurochs | 2 | animal | temperate plains |
| Herd Animal, Bison | 4 | animal | cold or temperate plains |
| Herd Animal, Camel | 1 | animal | warm deserts |
| Herd Animal, Elk | 1 | animal | cold or temperate plains |
| Herd Animal, Giraffe | 3 | animal | warm plains |
| Herd Animal, Ram | 1 | animal | temperate mountains |
| Herd Animal, River Elk | 2 | animal | cold or temperate plains |
| Herd Animal, Stag | 1 | animal | any land |
| Herecite, Herecite of Asmodeus | 9 | undead | any |
| Herecite, Herecite of Asmodeus | 9 | undead | any |
| Herne | 6 | monstrous humanoid | temperate forests |
| Hippocampus | 1 | magical beast (aquatic) | any water |
| Hippogriff | 2 | magical beast | temperate hills or plains |
| Hippopotamus | 5 | animal | warm rivers |
| Hippopotamus, Behemoth Hippopotamus | 10 | animal | warm rivers |
| Hiracapath | 7 | outsider (extraplanar, good, lawful) | any (Heaven) |
| Hive Mind Beetle Swarm | 13 | magical beast (swarm) | temperate forests |
| Hive, Hive Brute | 8 | aberration (Hive) | any |
| Hive, Hive Larva Swarm | 5 | aberration (hive, swarm) | any |
| Hive, Hive Queen | 10 | aberration (hive) | any |
| Hive, Hive Warrior | 5 | aberration (hive) | any |
| Hivemind Rat Swarm | 8 | magical beast (swarm) | any |
| Hoary Muntjac | 3 | magical beast | cold mountains |
| Hobbe Hound | 2 | animal | temperate hills or underground |
| Hobgoblin | 1/2 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Battle Priest | 8 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Battlefield Zealot | 2 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Bombardier | 7 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Commander | 12 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Forerunner | 6 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Lieutenant | 4 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Paragon | 10 | humanoid (goblinoid) | temperate hills |
| Hobgoblin, Hobgoblin Sergeant | 2 | humanoid (goblinoid) | temperate hills |
| Hodag | 6 | magical beast | temperate forests or marshes |
| Hollow One | 10 | construct | any |
| Hollow Serpent | 16 | undead | any underground |
| Hollow Serpent, Lesser Hollow Serpent | 6 | undead (reptilian) | — |
| Homunculus | 1 | construct | any |
| Hooded Harbinger | 12 | aberration | any |
| Hook Fly, Giant Hook Fly | 2 | vermin | any |
| Hook Fly, Hook Fly Swarm | 1 | vermin (swarm) | any |
| Hookfang Worm | 7 | vermin (aquatic) | any oceans |
| Horla | 8 | aberration (extraplanar) | any (Ethereal plane) |
| Horse | 1 | animal | temperate plains |
| Horse, Pony | 1/2 | animal | temperate plains |
| Horsemen of the Apocalypse, Apollyon | 29 | outsider (daemon, evil, extraplanar) | any (Abaddon) |
| Horsemen of the Apocalypse, Charon | 30 | outsider (daemon, evil, extraplanar) | any (Abaddon) |
| Horsemen of the Apocalypse, Szuriel | 28 | outsider (daemon, evil, extraplanar) | any (Abaddon) |
| Horsemen of the Apocalypse, Trelmarixian | 27 | outsider (daemon, evil, extraplanar) | any (Abaddon) |
| Hound of Tindalos | 7 | outsider (evil, extraplanar) | any |
| House Drake | 2 | dragon | urban (Korvosa) |
| House Spirit, Domovoi | 3 | fey | any land |
| House Spirit, Dvorovoi | 4 | fey | any land |
| House Spirit, Ovinnik | 2 | fey | any land |
| Howler | 3 | outsider (chaotic, evil, extraplanar) | any land (Abyss) |
| Huecuva | 2 | undead | any |
| Huldra | 4 | fey | cold forests or mountains |
| Humbaba | 19 | monstrous humanoid | any forests |
| Hundun | 21 | aberration (chaotic, extraplanar) | any (Abyss, Limbo, or Negative Energy Plane) |
| Hungry Flesh | 3 | ooze | any land or underground |
| Hungry Fog | 6 | ooze | any temperate |
| Hungry Mist | 14 | undead (incorporeal, swarm) | — |
| Hunting Horror | 14 | magical beast | any |
| Hupia | 6 | undead | any land |
| Hyakume | 15 | aberration | any underground |
| Hyaleth | 10 | aberration (aquatic) | temperate fresh water or underground |
| Hydra | 4 | magical beast | temperate marshes |
| Hydra, Dhirgiska | 13 | magical beast | — |
| Hyena | 1 | animal | warm plains |
| Hyena, Dire Hyena (Hyaenodon) | 3 | animal | warm plains |
| Hypnalis | 5 | outsider (extraplanar) | any (Ethereal Plane) |