| Creature | Terrain | Climate | Campaign | Reference |
|---|---|---|---|---|
| Algoid | Swamp | Temperate | Any | FF 11 |
| Alguduir (Swamp Dragon) | Swamp | Any | Forgotten Realms | FR2MC |
| Alguduir, Young | Swamp | Any | Forgotten Realms | FR2MC |
| Babbler | Swamp | Any | Any | FF 13 |
| Behemoth | Swamp | Any | Any | LL 167 |
| Boobrie | Swamp | Temp/Trop | Any | MM 27 |
| Bullywug | Swamp | Temp/Trop | Any | MM 34 |
| Bullywug, Advanced | Swamp | Temp/Trop | Any | MM 34 |
| Bullywug, Chieftain | Swamp | Temp/Trop | Any | MM 34 |
| Bullywug, Leader | Swamp | Temp/Trop | Any | MM 34 |
| Bullywug, Subchieftain | Swamp | Temp/Trop | Any | MM 34 |
| Bullywug, Subleader | Swamp | Temp/Trop | Any | MM 34 |
| Bvanen | Swamp | Tropical | Dark Sun | MAIII 18 |
| Campestri | Swamp | Any | Any | MAI |
| Catoblepas | Swamp | Any | Any | MM 39 |
| Crocodile | Swamp | Sub-Trop/Trop | Any | MM 49 |
| Crocodile, Giant | Swamp | Sub-Trop/Trop | Any | MM 49 |
| Darter | Swamp | Temp/Trop | Any | FFMC |
| Dinosaur, Brontosaurus | Swamp | Any | Any | MAII 35 |
| Dinosaur, Camarasaurus | Swamp | Any | Forgotten Realms | FR1MC |
| Dinosaur, Cetiosaurus | Swamp | Any | Forgotten Realms | FR1MC |
| Dinosaur, Diplodocus | Swamp | Any | Any | MM 54 |
| Dinosaur, Mamenchisaurus | Swamp | Any | Forgotten Realms | FR1MC |
| Dinosaur, Tanystropheus | Swamp | Any | Any | MAII 39 |
| Dog, Bog Hound | Swamp | Any | Any | MAII 42 |
| Dog, Moor Hound | Swamp | Any | Any | MAII 42 |
| Eblis, Common | Swamp | Temp/Trop | Any | MM 27 |
| Eblis, Spellcaster | Swamp | Temp/Trop | Any | MM 27 |
| Fachan (Gruumsh-kin) | Swamp | Any | Forgotten Realms | FR2MC |
| Froghemoth | Swamp | Any | Any | MAII 59 |
| Garbug, Violet | Swamp | Any | Any | MAI |
| Giant, Fog | Swamp | Temperate | Any | MM 138 |
| Gibbering Mouther | Swamp | Any | Any | MAI |
| Grung | Swamp | Sub-Trop/Trop | Greyhawk | GHMC |
| Grung, Juvenile | Swamp | Sub-Trop/Trop | Greyhawk | GHMC |
| Grung, Shaman | Swamp | Sub-Trop/Trop | Greyhawk | GHMC |
| Grung, Tadpole | Swamp | Sub-Trop/Trop | Greyhawk | GHMC |
| Hound, Fen- | Swamp | Any | Ravenloft | RVIII 37 |
| Kingfisher | Swamp | Temp/Trop | Any | MM 27 |
| Laraken | Swamp | Any | Any | MAI |
| Leech, Giant | Swamp | Temperate | Any | MM 219 |
| Leech, Magical | Swamp | Any | Ravenloft | RVIII 67 |
| Leech, Psionic | Swamp | Any | Ravenloft | RVIII 68 |
| Leech, Swarm | Swamp | Temperate | Any | MM 219 |
| Leech, Throat | Swamp | Temperate | Any | MM 219 |
| Lizard King | Swamp | Temp/Trop | Any | MM 227 |
| Lizard Man | Swamp | Temp/Trop | Any | MM 227 |
| Lizard Man, Advanced | Swamp | Temp/Trop | Any | MM 227 |
| Lizard Man, Bakali | Swamp | Sub-Trop/Trop | Dragonlance | DLMC |
| Lizard Man, Jarak-Sinn | Swamp | Temp/Trop | Dragonlance | DLMC |
| Lizard Man, Jarak-Sinn, Acolyte | Swamp | Temp/Trop | Dragonlance | DLMC |
| Lizard Man, Jarak-Sinn, Shaman | Swamp | Temp/Trop | Dragonlance | DLMC |
| Lungfish, Giant (Bichir) | Swamp | Any | Forgotten Realms | FR1MC |
| Lungfish, Giant, Young (Bichir) | Swamp | Any | Forgotten Realms | FR1MC |
| Lycanthrope, Devil Swine | Swamp | Temp/Trop | Any | DRC 190 |
| Lycanthrope, Werecrocodile | Swamp | Any | Any | MAIII 75 |
| Marl | Swamp | Temp/Trop | Any | MAII 85 |
| Mist, Crimson Death | Swamp | Any | Any | MM 253 |
| Mist, Scarlet Dancer | Swamp | Any | Any | MAIII 81 |
| Mist, Vampiric | Swamp | Temp/Trop | Any | MM 254 |
| Moss, Vampire | Swamp | Sub-Trop/Trop | Any | MAI |
| Muckdweller | Swamp | Temp/Trop | Any | MM 259 |
| Pudding, Brown | Swamp | Any | Any | MM 297 |
| Rohch, Swamp | Swamp | Any | Forgotten Realms | FR2MC |
| Shambling Mound | Swamp | Any | Any | MM 293 |
| Spider, Salt | Swamp | Any | Any | LL 167 |
| Termite, Water, Swamp | Swamp | Any | Any | DRC 209 |
| Twilight Bloom | Swamp | Temperate | Any | MAII 95 |
| Vulture, Marsh | Swamp | Any | Any | LL 169 |
| Wastrel | Swamp | Any | Planescape | PSII 122 |
| Will o'wisp | Swamp | Any | Any | MM 361 |
| Wyndlass | Swamp | Temperate | Dragonlance | DLMC |
| Xantravar | Swamp | Any | Any | MAI |