| Name | CR | Type | Environment |
| Calathgar | 4 | plant | cold forests |
| Caliban | 2 | monstrous humanoid | temperate and warm forests and marshes |
| Caligraphy Wyrm | 2 | dragon | any urban |
| Calikang | 12 | monstrous humanoid | temperate or tropical hills |
| Caller in Darkness | 9 | undead (incorporeal) | any |
| Calpina | 3 | fey | temperate forests or mountains |
| Cameroceras | 11 | animal (aquatic) | any oceans |
| Camulatz | 9 | magical beast | tropical jungles |
| Candlestone Courtier | 12 | fey | any underground (Darklands) |
| Canopy Creeper | 8 | plant | warm forests |
| Capacitor Ooze | 11 | ooze | cold deserts or plains |
| Capramace | 7 | aberration | temperate plains |
| Carbuncle | 1 | magical beast | any forests or swamps |
| Carnivorous Blob | 13 | ooze
| any
|
| Carnivorous Crystal | 11 | ooze (earth, extraplanar) | any underground (Plane of Earth) |
| Carrion Creeper | 10 | plant | temperate forests or plains |
| Carrionstorm | 1 | undead (swarm)
| any near ghouls
|
| Caryatid Column | 3 | construct | any |
| Cassomir Stray | 4 | aberration | any urban |
| Cat Sith | 2 | magical beast | temperate hills |
| Cat, Cheetah | 2 | animal | warm plains |
| Cat, Leopard | 2 | animal | any forest |
| Caterpillar, Blood Caterpillar | 4 | vermin | temperate or warm forests |
| Caterpillar, Horn Caterpillar | 1 | vermin | temperate or warm forests |
| Catfolk | 1/2 | humanoid (catfolk) | any temperate or warm forest or plains, or urban |
| Catoblepas | 12 | magical beast
| any swamps
|
| Caulborn | 7 | outsider (extraplanar) | any |
| Caulborn, Caulborn Thoughtkeeper | 9 | outsider (extraplanar) | any |
| Caulborn, Chrestomath | 6 | outsider (extraplanar) | any |
| Cauldron Bloom | 15 | plant | any cold land |
| Caustic Stalker | 7 | outsider (air, elemental, extraplanar) | any underground |
| Cave Fisher | 2 | vermin | any underground |
| Cayhound | 5 | outsider | any (Elysium) |
| Caypup | 2 | outsider (native) | any land |
| Cecaelia | 5 | monstrous humanoid (aquatic) | warm water |
| Celedon | 1 | construct | any |
| Centaur | 3 | monstrous humanoid | temperate forests and plains |
| Centaur, Centaur Charger | 14 | monstrous humanoid | temperate forests and plains |
| Centaur, Centaur Forager | 6 | monstrous humanoid | temperate forests and plains |
| Centaur, Centaur Greenspeaker | 4 | monstrous humanoid | temperate forests and plains |
| Centaur, Centaur Outcast | 7 | monstrous humanoid | temperate forests and plains |
| Centianima | 4 | undead | any ruins |
| Centipede, Centipede Swarm | 4 | vermin (swarm) | temperate or warm forest or underground |
| Centipede, Giant Centipede | 1/2 | vermin | temperate or warm forest or underground |
| Centipede, Giant Whiptail Centipede | 3 | vermin
| temperate or warm forests or underground
|
| Centipede, Titan Centipede | 9 | vermin
| temperate or warm forests or underground
|
| Cephalophore | 8 | construct | any |
| Ceratioidi | 3 | monstrous humanoid (aquatic) | any saltwater |
| Cerberi | 6 | outsider (evil, extraplanar, lawful) | any (Hell) |
| Cerberus Worm | 14 | magical beast (aquatic) | any oceans |
| Cerebric Cyst | 7 | ooze | any ruins or underground |
| Cerebric Fungus | 3 | plant | any |
| Ceru | 2 | magical beast | any urban (Vudra) |
| Cervine Protector | 6 | outsider (extraplanar, good, lawful) | any (Heaven) |
| Cerynitis | 7 | magical beast | any plains, hills, or forests |
| Cetacean, Blue Whale | 12 | animal | any oceans |
| Cetacean, Blue Whale | 12 | animal | any ocean |
| Cetacean, Crimson Whale | 8 | animal | any ocean |
| Cetacean, Narwhal | 3 | animal | cold oceans |
| Cetacean, Narwhal | 3 | animal | cold oceans |
| Cetus | 13 | dragon (aquatic, water) | any oceans |
| Chained Spirit | 14 | undead (incorporeal) | any |
| Chalkost | 4 | outsider (extraplanar, good, lawful, shapechanger) | any (Heaven) |
| Changeling | 1/2 | humanoid (changeling) | any |
| Chaos Beast | 7 | outsider (chaotic, extraplanar)
| any
|
| Charau-ka | 2 | humanoid (charau-ka) | warm forests |
| Charau-ka, Deadfall Tracker | 5 | humanoid | warm forests |
| Charau-ka, Devotee of the Ravener King | 7 | humanoid (charau-ka) | warm forests |
| Charau-ka, Jungle Trickster | 8 | humanoid (charau-ka) | warm forests |
| Charau-ka, Simian Sharpshooter | 6 | humanoid (charau-ka) | warm forests |
| Charda | 7 | monstrous humanoid (aquatic)
| cold aquatic or underground
|
| Charnel Colossus | 19 | undead | any (Kalexcourt, Ustalav) |
| Charnel God | 23 | construct | any |
| Charybdis | 13 | aberration (aquatic)
| any oceans
|
| Chatterer Swarm | 8 | outsider (chaotic, evil) | The Worldwound |
| Chelarac | 8 | aberration | any underground |
| Chelarac, Chelarac Broodling | 2 | aberration | — |
| Chemosit | 4 | magical beast | warm forests |
| Cherufe | 13 | magical beast (fire) | any mountains |
| Chickcharney | 3 | magical beast | warm forests, hills, or plains |
| Child of Yog-Sothoth | 7 | aberration (augmented humanoid) | any |
| Chimara, Legendary Chimera | 13 | magical beast | — |
| Chimera | 7 | magical beast | temperate hills |
| Chitikin | 4 | vermin | temperate or warm forests or underground |
| Choker | 2 | aberration | any underground |
| Choking Shade | 5 | undead (incorporeal) | any |
| Chon Chon | 1/2 | aberration | temperate or tropical forests or ruins |
| Chon Chon, Chon Chon Swarm | 3 | aberration (swarm) | temperate or tropical forests or ruins |
| Choxani | 3 | fey | any (First World) |
| Chronogeist | 14 | undead (incorporeal) | Crystilan (Xin-Edasseril) |
| Chupacabra | 3 | magical beast
| warm hills or plains
|
| Chuspiki | 2 | magical beast (air) | warm hills or mountains |
| Chuul | 7 | aberration (aquatic) | temperate swamps |
| Chuul, Chuul, Lesser | 4 | aberration (aquatic) | — |
| Chuul, Larval Chuul | 1 | aberration (aquatic) | — |
| Chyzaedu | 10 | aberration | any |
| Cicada, Cicada Swarm | 2 | vermin (swarm) | temperate forests |
| Cicada, Giant Cicada | 1 | vermin | any temperate or tropical land |
| Cinder Wolf | 2 | magical beast | temperate or warm deserts |
| Cinderghost | 7 | undead (extraplanar, fire, incorporeal) | any plains (Plane of Fire) |
| Cipactli | 21 | magical beast (aquatic) | any water |
| Clawbat | 1 | magical beast | temperate hills and ruins |
| Cloaker | 5 | aberration | underground |
| Clockwork, Clockwork Angel | 15 | construct (clockwork) | any |
| Clockwork, Clockwork Assassin | 13 | construct (clockwork) | any |
| Clockwork, Clockwork Dragon | 16 | construct (clockwork) | any land |
| Clockwork, Clockwork Excavator | 10 | construct (clockwork) | any land |
| Clockwork, Clockwork Familiar | 2 | construct (clockwork) | any |
| Clockwork, Clockwork Fiend | 17 | construct (clockwork) | any |
| Clockwork, Clockwork Goblin | 3 | construct (clockwork) | any |
| Clockwork, Clockwork Goliath | 19 | construct (clockwork) | any |
| Clockwork, Clockwork Guardian | 8 | construct (clockwork) | any |
| Clockwork, Clockwork Gunslinger | 7 | construct (clockwork) | any |
| Clockwork, Clockwork Hound | 5 | construct (clockwork) | any |
| Clockwork, Clockwork Leviathan | 12 | construct (clockwork) | any |
| Clockwork, Clockwork Mage | 9 | construct (clockwork) | any land |
| Clockwork, Clockwork Nautiloid | 14 | construct (clockwork) | any water |
| Clockwork, Clockwork Overseer | 7 | construct (clockwork) | any land |
| Clockwork, Clockwork Priest | 11 | construct (clockwork) | any |
| Clockwork, Clockwork Servant | 2 | construct (clockwork) | any |
| Clockwork, Clockwork Snail | 10 | construct (clockwork) | any |
| Clockwork, Clockwork Soldier | 6 | construct (clockwork) | any |
| Clockwork, Clockwork Songbird | 1/2 | construct (clockwork) | any |
| Clockwork, Clockwork Spy | 1/2 | construct (clockwork) | any |
| Clockwork, Clockwork Steed | 6 | construct (clockwork) | any land |
| Clockwork, Clockwork Vivisectionist | 10 | construct (clockwork) | any |
| Clockwork, Mechanical Efreeti | 1 | construct (clockwork) | — |
| Clockwork, Toy Golem | 5 | construct (clockwork) | — |
| Cockatrice | 3 | magical beast | temperate plains |
| Cockroach, Cockroach Swarm | 2 | vermin (swarm)
| any temperate, warm, or urban
|
| Cockroach, Flesh-Eating Cockroach Swarm | 2 | vermin | any temperate, warm, or urban |
| Cockroach, Giant Cockroach | 1/2 | vermin
| any land
|
| Cockroach, Monstrous Cockroach | 1/2 | vermin | any temperate, warm, or urban |
| Coeurl | 8 | magical beast | any land |
| Coffin Anemone | 1 | vermin (aquatic) | temperate coastlines or oceans |
| Cold Rider | 8 | fey (cold) | any cold |
| Colour Out of Space | 10 | ooze (incorporeal) | any |
| Combusted | 3 | undead (fire) | any |
| Commando Construct | 9 | construct (augmented, robot) | any |
| Comozant Wyrd | 4 | outsider (air, elemental, extraplanar, incorporeal) | any oceans (during storms) |
| Conqueror Worm | 21 | aberration | any |
| Contemplative | 2 | monstrous humanoid | any urban |
| Contemplative, Enlightened Contemplative | 5 | monstrous humanoid | any urban |
| Copsewight | 11 | undead | any forest |
| Coral Capuchin | 1 | magical beast (aquatic) | warm coasts or oceans |
| Corbayrant | 16 | magical beast | temperate forests |
| Cordulegaster | 6 | outsider (aquatic, evil, extraplanar) | any freshwater (River Styx) |
| Cordulegaster, Elder Cordulegaster | 7 | outsider (aquatic, daemon, evil, extraplanar) | any freshwater (River Styx) |
| Corpse Lotus | 13 | plant | temperate forests or marshes |
| Coryphae | 6 | fey | any underground or urban |
| Couatl | 10 | outsider (native) | warm forests |
| Couatl, Auwaz Couatl | 6 | outsider (native) | any |
| Couatl, Chicome | 16 | outsider (native) | warm badlands or ruins |
| Couatl, Lord Sun-Warrior | 15 | outsider (native) | — |
| Couatl, Mix Couatl | 8 | outsider (native) | any |
| Couatl, Tletli | 14 | outsider (native) | any |
| Couatl, Xiuh Couatl | 12 | outsider (native) | any mountain |
| Crab, Crab Swarm | 4 | vermin (aquatic, swarm) | any aquatic |
| Crab, Giant Crab | 2 | vermin (aquatic) | any aquatic |
| Crab, Shark-Eating Crab | 7 | vermin (aquatic) | any water |
| Crab, Shipwrecker Crab | 13 | vermin (aquatic) | any water |
| Crackling Skull Swarm | 10 | undead (swarm) | any |
| Crag Spider | 8 | vermin | cold mountains |
| Crawling Hand | 1/2 | undead
| any land
|
| Crawling Hand, Giant Crawling Hand | 5 | undead
| any land or underground
|
| Crepitus | 5 | outsider (evil, extraplanar, lawful) | Hell |
| Crimson Jellyfish | 4 | vermin (aquatic) | temperate oceans |
| Croaker | 5 | undead (incorporeal) | any land (usually urban) |
| Crocodile | 2 | animal | warm rivers and marshes |
| Crocodile, Dire Crocodile | 9 | animal | warm rivers and marshes |
| Crocodile, Hetkoshu | 12 | animal | warm marshes or rivers |
| Crocodilians, Deinosuchus | 8 | animal | any water |
| Crocodilians, Marine Crocodile | 3 | animal | tropical oceans |
| Crocodilians, Saltwater Crocodile | 5 | animal | tropical coasts and rivers |
| Crone Queen | 15 | undead (cold) | cold ruins |
| Cruciarus | 12 | undead (incorporeal) | any |
| Crypt Flower | 7 | plant | any land |
| Crypt Thing | 5 | undead
| any underground
|
| Cryptguard | 9 | construct | any |
| Crysmal | 3 | outsider (earth, elemental)
| any underground (Plane of Earth)
|
| Cuero | 5 | aberration (aquatic) | temperate lakes or rivers |
| Cursed King | 10 | undead | warm ruins |
| Cutlass Spider | 6 | construct | any |
| Cyclops | 5 | humanoid (giant) | any temperate or tropical |
| Cyclops, Cyclops Grand-Eye | 10 | humanoid (giant) | any temperate or tropical |
| Cyclops, Cyclops Lorekeeper | 13 | humanoid (giant) | any temperate or tropical |
| Cyclops, Cyclops Manhunter | 7 | humanoid (giant) | any temperate or tropical |
| Cyclops, Cyclops Smasher | 9 | humanoid (giant) | any temperate or tropical |
| Cyclops, Great Cyclops | 12 | humanoid (giant) | any temperate or tropical |
| Cyclops, Kabandha | 9 | humanoid (giant) | any land or underground |
| Cyclops, Oracular Cyclops | 7 | humanoid (giant) | any temperate or tropical |
| Cyclops, Savage Great Cyclops | 18 | humanoid (giant) | any temperate or tropical |
| Cynosoma | 12 | outsider (chaotic, extraplanar, good) | any (Cynosure, Elysium) |
| Cyphergull | 2 | magical beast | temperate coasts |
| Cytillesh Zombie | 1 | undead | — |
| Cytillipede | 6 | magical beast | any underground |