A |
| Name | CR | Source |
| Abroan | 2 | Monster Geographica Underground |
| Acidweaver | 5 | Ultimate Monsters 1, Monster Geographica Underground |
| Addlevetch | 1 | Monster Geographica Underground |
| Albine | 4 | Minions Rebirth, Monster Geographica Underground |
| Ambush | 2 | Monster Geographica Underground |
| Amohaji | 5 | Monsters of the Mind, Monster Geographica Underground |
| Arachnogolem | 12 | Ultimate Monsters 1, Monster Geographica Underground |
| Arachnomorph | 6 | Ultimate Monsters 1, Monster Geographica Underground |
| Arachnopygmy | 2 | Monster Geographica Underground |
| Arcanoplasm | 7 | Tome of Horrors 2, Monster Geographica Underground |
| Artificeer | 13 | Monster Geographica Underground |
| Ascomoid | 4 | Dungeonscape, Tome of Horrors 1, Dragon#68, 1E Monster Manual 2, Monstrous Compendium Volume 2, Monstrous Manual, Monster Geographica Underground |
B |
| Name | CR | Source |
| Banded Spider | 6 | Monster Geographica Underground |
| Banded Spider, Mother | 12 | Monster Geographica Underground |
| Bandersnatch | 4 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Barangulaak | 16 | Monster Geographica Underground |
| Barathelar | 7 | Monster Geographica Underground |
| Basidirond | 5 | Dragon#337, Tome of Horrors 1, Dragon#68, 1E Monster Manual 2, Monster Geographica Underground |
| Bedlam | 9 | Tome of Horrors 2, Monster Geographica Underground |
| Beetle, Giant - Death Watch | 6 | Tome of Horrors 1, 1E Monster Manual 2, Monstrous Compendium Annual 3, Greyhawk (MC5), Monster Geographica Underground |
| Bhuta (II) | 3 | Monsters of the Mind, Monster Geographica Underground |
| Blackwater Slough | 15 | Monster Geographica Underground |
| Blind Maw | 7 | Monster Geographica Underground |
| Blood Ooze | 6 | Monster Geographica Underground |
| Blood Pool | 2 | Ultimate Monsters 1, Monster Geographica Underground |
| Bolrow | 8 | Monster Geographica Underground |
| Bone Sovereign | 5 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Brainlock Spider | Varies | Ultimate Monsters 1, Monster Geographica Underground |
| Brilkoun | 11 | Monster Geographica Underground |
| Burrower | 8 | Monster Geographica Underground |
C |
| Name | CR | Source |
| Cave Beetle | 1 | Ultimate Monsters 1, Monster Geographica Underground |
| Cave Fisher | 2 | Tome of Horrors 1, In the Dungeons of the Slave Lords (A4), 1E Monster Manual 2, Monstrous Compendium Volume 1, Monstrous Manual, Black Spine, Monster Geographica Underground |
| Cave Hermit | 6 | Monster Geographica Underground |
| Cave Keeper | 10 | Monster Geographica Underground |
| Cave Leech | 6 | Tome of Horrors 2, Monster Geographica Underground |
| Cave Star | 2 | Monster Geographica Underground |
| Cavern Giant | 7 | Monster Geographica Underground |
| Cavern Wolf | 2 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Cavernivore | 10 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Ceiling Diver | 3 | Monster Geographica Underground |
| Celler Dweller | 1/3 | Monster Geographica Underground |
| Centioch | 4 | Monster Geographica Underground |
| Chamber Worm | 8 | Monster Geographica Underground |
| Charrel | 6 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Chitinous Battlemounts | 2 | Ultimate Monsters 1, Monster Geographica Underground |
| Cinder Wight | 7 | Monster Geographica Underground |
| Coblynan | 1 | Monster Geographica Underground |
| Compost Seeker | 4 | Monster Geographica Underground |
| Cone Ooze | 9 | Monster Geographica Underground |
| Corpse Fungus | 1/2 | Monster Geographica Underground |
| Crag Man | 5 | Tome of Horrors 2, Monster Geographica Underground |
| Crorit | 9 | Monster Geographica Underground |
| Crypt Guardian | 5 | Tome of Horrors 1, 1E Fiend Folio, Monster Geographica Underground |
| Crypt Thing | 3 | 3E Fiend Folio, Tome of Horrors 1, Monster Geographica Underground, 1E Fiend Folio, Dragon#55, Greyhawk (MC5), Monstrous Manual |
| Crystal Moss | 3 | Monster Geographica Underground |
| Crystal Serpent | 1 | Monster Geographica Underground |
D |
| Name | CR | Source |
| Dagger Worm | 7 | Monster Geographica Underground |
| Dark Elf Spirit | 5 | Monster Geographica Underground |
| Dark Voyeur | 3 | Monster Geographica Underground |
| Daurzam | 1 | Monster Geographica Underground |
| Deep Fey | 1 | Monster Geographica Underground |
| Deviant Mimic | 3 | Monster Geographica Underground |
| Dorje Ooze | 4 | Monsters of the Mind, Monster Geographica Underground |
| Draconid | 9 | Tome of Horrors 2, Monster Geographica Underground |
| Drone Weaver | 2 | Ultimate Monsters 1, Monster Geographica Underground |
| Drudge Crawler | 5 | Ultimate Monsters 1, Monster Geographica Underground |
E |
| Name | CR | Source |
| Eldlorn | 1/3 | Monster Geographica Underground |
| Erolth | 4 | Monster Geographica Underground |
| Ethereal Adder | 7 | Monster Geographica Underground |
| Ethereal Assassin | 7 | Monster Geographica Underground |
| Eye Killer | 3 | Tome of Horrors 1, 1E Fiend Folio, Monster Geographica Underground |
F |
| Name | CR | Source |
| Fear Guard | 5 | Tome of Horrors 2, Monster Geographica Underground |
| Flosid | 2 | Monster Geographica Underground |
| Fluttering Ooze | 1/4 | Monster Geographica Underground |
| Foul Spawner | 2 | Monster Geographica Underground |
| Fulgurate Mushrooms | 4 | Tome of Horrors 2, Monster Geographica Underground |
| Fungal Render | 6 | Monster Geographica Underground |
G |
| Name | CR | Source |
| Gate Worm | 12 | Creature Collection 3, Monster Geographica Underground |
| Gholimor | 7 | Monster Geographica Underground |
| Ghoul, Gormul | 12 | Creature Collection 3, Monster Geographica Underground |
| Gloom Crawler | 8 | Tome of Horrors 2, Monster Geographica Underground |
| Gnishma | 18 | Monster Geographica Underground |
| Golem, Furnace | 14 | Tome of Horrors 2, Spelljammer (MC7), Monster Geographica Underground |
| Golem, Gravel | 7 | Ultimate Monsters 1, Monster Geographica Underground |
| Golem, Iron Maiden | 9 | Tome of Horrors 2, Monster Geographica Underground |
| Golem, Rope | 13 | Monster Manual 3, Tome of Horrors 2, Spells and Spellcraft, Dragon#302, Monster Geographica Underground |
| Gore Mole | 4 | Ultimate Monsters 1, Monster Geographica Underground |
| Gorgotaur | 6 | Ultimate Monsters 1, Monster Geographica Underground |
| Grasping Cell | 7 | Monster Geographica Underground |
| Gremmin | 3 | Monster Geographica Underground |
| Grimvole | 3 | Monster Geographica Underground |
| Grimvole, Grim Master | 8 | Monster Geographica Underground |
| Grindgut Spitter | 3 | Ultimate Monsters 1, Monster Geographica Underground |
| Groundling (II) | 2 | Minions Rebirth, eMinions Cunning Creatures, Monster Geographica Underground |
| Gutslinger | 3 | Monster Geographica Underground |
| Gutslug | 3 | Tome of Horrors 2, Monster Geographica Underground |
| Gutwrench | 8 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
H |
| Name | CR | Source |
| Haemovorid | 3 | Ultimate Monsters 1, Monster Geographica Underground |
| Hellscorn | 9 | Monster Geographica Underground |
| Higher Elemental, Gnomide | 4 | Ultimate Monsters 1, Monster Geographica Underground |
| Horach | 4 | Monster Geographica Underground |
| Huggermugger | 1 | Tome of Horrors 2, Monster Geographica Underground |
| Hypnogrub | 6 | Monster Geographica Underground |
I |
| Name | CR | Source |
| Igran-Krider | 1 | Monster Geographica Underground |
| Inscriber | 4 | Monster Geographica Underground |
J |
| Name | CR | Source |
| Jellyhive | 5 | Monster Geographica Underground |
K |
| Name | CR | Source |
| Ka Spirit | 5 | Minions Rebirth, eMinions Cunning Creatures, Monster Geographica Underground |
| Kulkum | 1 | Monster Geographica Underground |
L |
| Name | CR | Source |
| Lassoo | 2 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Lava Lurker | 6 | Monster Geographica Underground |
| Lavum | 3 | Monster Geographica Underground |
| Leech Bat | 1/2 | Monster Geographica Underground |
| Leytru | 7 | Monster Geographica Underground |
| Living Web (III) | 2 | Monster Geographica Underground |
| Lizard, Cavern | 4 | Tome of Horrors 2, Monster Geographica Underground |
M |
| Name | CR | Source |
| Magma Worm | 14 | Ultimate Monsters 1, Monster Geographica Underground |
| Mal'Orm | 6 | Monster Geographica Underground |
| Manavore | 6 | Monster Geographica Underground |
| Marloc | 8 | Monster Geographica Underground |
| Mawler | 4 | Tome of Horrors 2, Monster Geographica Underground |
| Mercury Ooze | 4 | Tome of Horrors 1, Monster Geographica Underground |
| Mirror Fiend | 7 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Morph | 7 | Monster Geographica Underground |
N |
| Name | CR | Source |
| Noja | 4 | Monster Geographica Underground |
| Nokker | 6 | Monster Geographica Underground |
| Norughk | 3 | Monster Geographica Underground |
| Nymorryx | 1 | Monster Geographica Underground, Ultimate Monsters 1 |
O |
| Name | CR | Source |
| Olivid | 4 | Monster Geographica Underground |
| Oozecrawler | 6 | Monster Geographica Underground |
| Ophean | 3 | Monster Geographica Underground |
| Ore Hound | 2 | Monster Geographica Underground |
| Orvender | 9 | Monster Geographica Underground |
| Ossecap | 8 | Monster Geographica Underground |
P |
| Name | CR | Source |
| Pallemon | 8 | Monster Geographica Underground |
| Palnor | 5 | Monster Geographica Underground |
| Pedra Wyrm | 12 | Monster Geographica Underground |
| Phantasm | 8 | Tome of Horrors 2, Monster Geographica Underground |
| Piryke | 12 | Monster Geographica Underground |
| Pompilian | 2 | Monster Geographica Underground |
| Pseudoslab | 4 | Ultimate Monsters 1, Monster Geographica Underground |
| Pudding, Blood | 5 | Tome of Horrors 2, Monster Geographica Underground |
| Pudding, Stone | 9 | Tome of Horrors 2, Monster Geographica Underground |
Q |
| Name | CR | Source |
| Quickener | 20 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
R |
| Name | CR | Source |
| Rahulh | 5 | Monster Geographica Underground |
| Rat, Barrow | 1/4 | Tome of Horrors 2, Monster Geographica Underground |
| Ravvimen | 2 | Monster Geographica Underground |
| Redcap | 2 | Monster Manual 3, Fang and Fury, Tome of Horrors 2, Monster Geographica Underground |
| Reliquary Guardian | 4 | Monster Geographica Underground |
S |
| Name | CR | Source |
| Sand Flail | 3 | Monster Geographica Underground |
| Screaming Skull | 4 | Tome of Horrors 2, Monster Geographica Underground |
| Shadow Ooze | 6 | Monster Geographica Underground |
| Silent Reaper | 7 | Monster Geographica Underground |
| Silid | 1/2 | Monster Geographica Underground |
| Singer | 3 | Monster Geographica Underground |
| Skeleton, Black | 5 | Tome of Horrors 2, Monster Geographica Underground |
| Skulleton | 3 | Ancient Kingdoms Mesopotamia, Tome of Horrors 1, Monster Geographica Underground |
| Skunk Goblin | 1/2 | Monster Geographica Underground |
| Slather | 8 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Slaughterford | 8 | Tome of Horrors 2, Monster Geographica Underground |
| Slavering Mouther | 10 | Monster Geographica Underground |
| Slime Crawler | 1 | Tome of Horrors 1, Monster Geographica Underground |
| Slithe | 1 | Monster Geographica Underground |
| Snailfolk | 1 | Monster Geographica Underground |
| Soot Goblin | 1 | Monster Geographica Underground |
| Soulless One | 13 | Monster Geographica Underground |
| Spectral Angler | 8 | Monster Geographica Underground |
| Spitting Ghoul | 4 | Monster Geographica Underground |
| Stallassein | 4 | Monster Geographica Underground |
| Stinkgnarl | 11 | Monster Geographica Underground |
| Stone Slug | 5 | Monster Geographica Underground |
| Stonemite | 0 | Monster Geographica Underground |
| Stonestrider | 4 | Ultimate Monsters 1, Monster Geographica Underground |
| Straga | 8 | Monster Geographica Underground |
| Swarm, Warden Jack | 4 | Tome of Horrors 2, Monster Geographica Underground |
| Symbiotic Jelly | 4 | Tome of Horrors 1, 1E Fiend Folio, 2E Fiend Folio (MC14), Monster Geographica Underground |
T |
| Name | CR | Source |
| Tentacled Horror | 10 | Tome of Horrors 2, Monster Geographica Underground |
| Teo-Selerai | 4 | Monster Geographica Underground |
| Time Spider | 6 | Monster Geographica Underground |
| Trapper | 7 | Ancient Kingdoms Mesopotamia, Tome of Horrors 1, Strategic Review#5, 1E Monster Manual 1, Monstrous Compendium Volume 2, Monstrous Manual, Monster Geographica Underground |
| Troll, Cave | 8 | Monster Manual 3, Dangerous Denizens, Tome of Horrors 1, Monster Geographica Underground |
| Troll, Rock | 6 | Trouble at Durbenford, Tome of Horrors 1, Monster Geographica Underground |
| Troll, Two-Headed | 6 | Tome of Horrors 1, 1E Fiend Folio, Monstrous Compendium Volume 1, Ultimate Monsters 1, Monstrous Manual, Monster Geographica Underground |
| Twilight Mushrooms | 7 | Tome of Horrors 1, Monster Geographica Underground |
| Tzorda | 18 | Monster Geographica Underground |
U |
| Name | CR | Source |
| Udamentaz | 6 | Minions Rebirth, eMinions Cunning Creatures, Monster Geographica Underground |
| Undal | 4 | Monster Geographica Underground |
| Undead Ooze (II) | 6 | Tome of Horrors 1, Monster Geographica Underground |
| Undermind | 15 | Monster Geographica Underground |
| Ushabti | 2 | Minions Rebirth, eMinions Cunning Creatures, Monster Geographica Underground |
V |
| Name | CR | Source |
| Vacuous Engulfer | 5 | Monster Geographica Underground |
| Vampire Spider | 11 | Ultimate Monsters 1, Monster Geographica Underground |
| Void Monster | 18 | Minions Rebirth, Minions: Fearsome Foes, Monster Geographica Underground |
| Vylar, Brood Mother | 16 | Monster Geographica Underground |
| Vylar, Greater | 9 | Monster Geographica Underground |
| Vylar, Lesser | 1 | Monster Geographica Underground |
W |
| Name | CR | Source |
| Wailhaunt | 7 | Monster Geographica Underground |
| Waking Dead | 3 | Monster Geographica Underground |
| Walking Disease | 12 | Monster Geographica Underground |
| Wurrgis | 2 | Monster Geographica Underground |
| Wyrdwolf | 5 | Monster Geographica Underground |
