At some point in history somebody decided to make up some of their own animals and beings, and sometimes the particular creature they made up was interesting enough that others kept using the same made up creatures in their stories.
For organisms with an intelligence about equal to humans or otherwise sapient which usually don't get wantonly slaughtered by heroes without moral repercussions, see Fantastic Sapient Species Tropes. See also Our Monsters Are Different. Note that this, like most things, is now subject to The Wiki Rule, as you can see here.
Tropes:
- Evil Race Tropes
- Fantastic Racism
- Fantastic Sapient Species Tropes
- Interracial and Interspecies Love Index
- Liminal Being
- Mix-and-Match Critters
- Not Quite Human
- Our Monsters Are Different
Specific types:
- Alien Tropes (extraterrestrials)
- Amphibian at Large (giant amphibians)
- Angelic Tropes (angels)
- Animal Anthropomorphism Tropes (human-like animals)
- Beast Man (humanoids with animal traits)
- Funny Animal Tropes (civilized and/or funny animal characters)
- Werebeast Tropes (werewolves and similar creatures)
- Cosmic Entity (all-powerful beings)
- God Tropes (gods and goddesses)
- Dragon Tropes (dragons)
- Eldritch Abomination
- Elf Tropes (elves)
- Fairy Tropes (elves, fairies, pixies, etc.)
- Fantastic Flora (bizarre, fantastical plant life)
- Genie Tropes (genies)
- Infernal Tropes (demons)
- Mer Tropes (mermaids/mermen)
- Tropes of the Divine (angels, gods, and goddesses)
- Undead Index (undead creatures)
- Haunted Index (ghosts)
- Mummy Tropes (mummies)
- Skeletal Tropes (skeletons)
- Tropes of the Living Dead (zombies)
- Vampire Tropes (vampires)
- Witches and Wizards
- Youkai (various creatures from Japanese folklore and mythology)
- Alien Animals: Extraterrestrial creatures look exactly like Earth animals.
- Alien Fair Folk: Extraterrestrials who look and act like mythical fairies.
- All Trolls Are Different: Because trolls can vary so significantly across many different works of fiction.
- Animal-Vehicle Hybrid: Animals that function as vehicles.
- Animated Armor: Living suits of armor.
- Animate Inanimate Matter: Living beings composed of a solid mass of normally nonliving matter.
- Anthropomorphic Personification: A humanlike sapient being (often a deity or spirit) that acts as a living embodiment of some sort of concept in human society or the natural world.
- Holiday Personification: An Anthropomorphic Personification of a holiday.
- Antlion Monster
- Asian Lion Dogs: Feline and/or canine beings, usually guardians of people and places.
- Asteroids Monster: A creature that divides into smaller versions of itself when defeated.
- Attack of the Killer Whatever
- Basilisk and Cockatrice: A bird/reptile creature with a deadly or petrifying gaze.
- Beast Man: Various creatures reminiscent of anthropomorphic animals. See the trope itself for its extensive list of subtypes.
- Benevolent Monsters: Creatures that look scary but are actually very friendly.
- Big Creepy-Crawlies: Giant arthropods.
- Bioweapon Beast: An artificially-created creature made to be a living weapon.
- Blob Monster: A living creature made of amorphous slime.
- Bond Creatures
- Brain Monster: A creature that consists mostly or entirely of a big, exposed brain.
- Brown Note Being
- Canis Major: Giant dogs.
- Carbuncle Creature
- Chest Monster: A monster that is disguised as a box or chest, luring in victims under the pretense of containing treasure or other valuable items.
- Classical Chimera: A monster made up of a lion, goat and snake.
- Classical Cyclops: A one-eyed, monstrous man-eating giant.
- Clock Roaches: Things that try to kill you if you mess around with time.
- Clockwork Creature
- Crystalline Creature: Living beings composed entirely of crystals or precious stones.
- Cthulhumanoid: A humanoid creature with squid-like features, reminiscent of Cthulhu.
- Cute Monster
- Cute Monster Girl: Female monsters who look prettier than their male counterparts.
- Cyclops: A creature with only one eye.
- Differently Powered Individual: A subcategory of the human species, consisting of people who have superhuman abilities.
- Mage Species: People who have the natural ability to use magic and sorcery.
- Divine Birds
- Eerie Anatomy Model
- Elemental Embodiment: Spirit beings that represent the Elements of Nature or Elemental Powers.
- Eldritch Abomination: An extremely weird, otherworldly being of unfathomable power.
- Energy Beings: Creatures that are not made of physical matter.
- Extremophile Lifeforms: Creatures that inhabit extreme environments inimical to more ordinary life.
- Fantastic Fauna Counterpart
- Fantastic Foxes: Magical creatures who resemble fox-like humanoids.
- Asian Fox-Spirit: Fox spirits from East Asian folklore. Includes the Japanese kitsune, the Chinese huli jing, and the Korean kumiho.
- Fantastic Livestock: Magical, alien, or otherwise otherworldly livestock.
- Fantastic Medicinal Bodily Product
- Fantastic Nature Reserve: A park or reserve where magical, alien, or otherwise fictional creatures live.
- Fantastic Vermin: Magical, alien, or otherwise otherworldly everyday pests.
- Fauns and Satyrs: Humanoid creatures with goat-like legs.
- Fearsome Critters of American Folklore: Various creatures from non-indigenous American folktales and legends.
- The Jersey Devil: A demonic creature that is said to live in the wilderness of New Jersey.
- Feathered Serpent: A snake or snake-like creature with feathers and/or avian wings.
- Female Monster Surprise: A creature turns out to be female.
- Formerly Sapient Species: A sapient species that has regressed to an animalistic state.
- Genius Loci: A physical location with a mind of its own.
- Giant Flyer
- Giant Space Flea from Nowhere: A video game features a boss fight where the boss shows up out of the blue without any prior foreshadowing, has no bearing on the plot and is never brought up again once defeated.
- Giant Spider: A giant spider.
- Golem: A human-shaped clay sculpture brought to life.
- Improvised Golems: Golems created from other materials in the surrounding environment.
- Snowlems: Snowmen that have been brought to life.
- Gorgeous Gorgon: A supposedly terrifying monster is revealed to be an attractive woman.
- The Greys: The common depiction of extraterrestrials as short, bald beings with gray skin and large, black eyes shaped like almonds.
- Griping About Gremlins
- Half-Human Hybrid: A being who is one-half human and one-half something that isn't human.
- Harping on About Harpies
- Have I Mentioned I Am a Dwarf Today?: Bragging about and being proud of belonging to a proud warrior race.
- The Heartless
- Hobbits
- Home of Monsters
- Horde of Alien Locusts
- Horned Humanoid: A humanoid creature with horns.
- Hu Mons: Mons that resemble human beings.
- Hybrid Monster: A monster with traits of two or more otherwise independent monster species.
- Hybrid Overkill Avoidance
- Insectoid Aliens: Aliens that look like insects, arachnids, or arthropods from Earth.
- Interspecies Adoption: A being adopts a child that is a different species.
- Interspecies Friendship: Friendship between beings of different species.
- Interspecies Romance: Romance between beings of different species.
- Invisible Monsters
- Kaiju: Gigantic monsters capable of demolishing an entire city, made popular by Japanese films such as Godzilla.
- Killer Space Monkey
- A Kind of One: Something that is a single, one-off entity in its original myth but becomes an entire species of similar creatures in fiction.
- Kirin
- The Krampus: A hairy, horned being who is believed to punish naughty children during Christmas.
- Lilliputians
- Little Bit Beastly
- Literal Bookworm: Wormly bugs that eat books, read books, or read books by eating them.
- Little Green Men: Short green aliens.
- Living Clothes
- Living Drawing: Artwork that has a mind of its own.
- Living Gasbag: Creatures that float by using organic sacs filled with lighter-than-air gases.
- Living Shadow: A being made of literal darkness.
- Living Ship
- Living Structure Monster
- Living Program
- Living Toys: Toys that are alive.
- MacGuffin Guardian
- Man-Eating Plant: A plant that eats people.
- Mechanical Lifeforms: Robotic creatures that act like natural wildlife.
- Mega-Microbes: Microbes large enough to be visible to the naked eye.
- Mega Neko: A giant cat.
- Mesopotamian Monstrosity: A demon or other villainous, supernatural character that originates from or is closely linked to Mesopotamian Mythology.
- Metamorphosis Monster
- Minorly Mentioned Myths and Monsters: Seldom-Seen Species applied to imaginary creatures or deities.
- Mokele-Mbembe: An aquatic dinosaur said to live deep within isolated jungles.
- Mole Men
- Monster Knight
- Monster Lord
- Monster Roommate: A nonhuman being who lives in a human's home.
- Monstrous Humanoid: A being shaped like a human, but has very obviously inhuman traits.
- Moon Rabbit: There are certain craters on the moon that look a bit like a rabbit, which folklore has seized upon
- The Morlocks: Subterranean, subhuman degenerates
- Muck Monster
- Mushroom Man: Intelligent, humanoid fungi.
- Mutants: Genetically abnormal organisms that look significantly different from normal members of their species.
- Nature Spirit: A spirit or deity associated with some aspect of the natural wilderness.
- Non-Human Head
- Non-Human Humanoid Hybrid: A being who is a mixture of two different non-human species.
- Non-Malicious Monster: Some monsters don't mean to cause trouble
- Nuckelavee: A monster resembling the torso of a man merged to the body of a horse, without skin.
- Nuclear Nasty: A monster created from exposure to radiation.
- One-Gender Race: An entire species that only has one biological sex.
- Oracular Head
- Ouroboros: A snake eating its own tail
- Our Angels Are Different: Holy spirit beings from Heaven who serve God.
- Celestial Paragons and Archangels: Powerful angels who run heavenly affairs, directly reporting to God Himself.
- Nephilim: A hybrid being that is often some mixture of angel, demon, and/or human.
- Our Archons Are Different: Gnostic supernatural ruling powers of the world.
- Our Banshees Are Louder
- Our Centaurs Are Different: Creatures with a human-like upper body on top of a horse-like lower body.
- Our Cryptids Are More Mysterious: Various creatures originating from (relatively modern) folklore and urban legends.
- Bigfoot, Sasquatch and Yeti: Various big, hairy ape-like creatures who live in seclusion. Bigfoot, Sasquatch, and the Yeti (or Abominable Snowman) are the three most common varieties.
- Big-Hearted Bigfoot: Bigfoot is portrayed as a kind-hearted figure, especially when contrasted with most other cryptids
- Chupacabra: A strange beast that is said to prey on goats and other livestock.
- The Flatwoods Monster: A red-faced, spade-headed alien creature that was allegedly seen near the town of Flatwoods, West Virginia in the 1950s.
- The Mothman: A bizarre Winged Humanoid creature that was allegedly seen near the town of Point Pleasant, West Virginia in the 1960s.
- Spring-Heeled Jack: A strange humanoid being from 19th century British folktales, who is capable of jumping great heights.
- Bigfoot, Sasquatch and Yeti: Various big, hairy ape-like creatures who live in seclusion. Bigfoot, Sasquatch, and the Yeti (or Abominable Snowman) are the three most common varieties.
- Our Demons Are Different: Evil spirits and monsters, usually from Hell or a similar bad place.
- Big Red Devil: The classic stereotypical demon that resembles a humanoid with red skin, horns, bat-like wings, goat-like legs, and a pointed tail. Often what one thinks of when "the Devil" is named.
- Demon Lords and Archdevils: Satan and other powerful demons who rule over Hell.
- Hellhound: Demonic beasts that resemble monstrous dogs.
- Hellish Horse: Demonic beasts that resemble nightmarish horses.
- Horny Devils: The incubus and succubus, which are (respectively) male and female demons that sexually seduce female and male humans for nefarious purposes.
- Our Dragons Are Different: Giant flying reptilian beasts, which usually resemble overgrown lizards and snakes.
- Catlike Dragons: Dragons with feline traits.
- The Dragons Come Back: Dragons were gone from the world, but are now returning.
- Feathered Dragons: Dragons with avian traits.
- Our Hydras Are Different: A multi-headed dragon-like monster originating from Greek mythology, known for its impressive regenerative abilities.
- Our Wyverns Are Different: Two-winged, two-legged, often poisonous dragons of limited intelligence.
- Shoulder-Sized Dragon: A dragon around the size of a cat.
- Our Fairies Are Different: A wide variety of magical humanoid beings, usually associated with European folklore.
- Faerie Court: Rulers amongst the fae.
- The Fair Folk: Fairies as strange, dangerous beings who like to mess with humans.
- House Fey
- Leprechaun: An Irish fairy that resembles a short man with red hair. Often associated with pots of gold and rainbows.
- Our Pixies Are Different: A tiny winged fairy.
- Our Gargoyles Rock: Not all gargoyles are just ugly statues on old buildings. Some of them are actually alive.
- Our Genies Are Different: The jinn are magical spirit beings originating from Arab/Muslim folklore. For some reason, they're usually trapped in lamps and forced to grant wishes for humans.
- Jackass Genie: Some genies make sure to intentionally twist their master's wish into something terrible.
- Literal Genie: Other genies may misunderstand the exact wording of one's wish, leading to it being granted wrongly.
- Our Giants Are Bigger: But what they all have in common are being much taller than humans.
- Our Gnomes Are Weirder
- Our Goblins Are Different
- Our Gods Are Different: Deities and other divine spirit beings, who are generally far more powerful than any human or other mortal creature.
- Our Gryphons Are Different
- Our Hippocamps Are Different
- Our Homunculi Are Different
- Our Imps Are Different
- Our Kelpies Are Different
- Our Kobolds Are Different
- Our Manticores Are Spinier
- Our Mermaids Are Different: Aquatic creatures with a half-human/half-fish appearance.
- Our Minotaurs Are Different: A half-man half-bull creature.
- Our Monsters Are Weird: Some creatures are very bizarre.
- Our Nymphs Are Different
- Our Ogres Are Hungrier
- Our Sirens Are Different
- Our Sphinxes Are Different
- Our Spirits Are Different: Spiritual entities can differ greatly from one another, depending on the type of spirit and the story they're in.
- Our Werebeasts Are Different: Someone turns into a different kind of were-animal besides a werewolf.
- Our Werewolves Are Different: Depictions of werewolves that differ from how fiction usually portrays them.
- Werewolves Are Dogs: Werewolves that behave like domestic dogs.
- Wolf Man: A very anthropomorphic werewolf, which tends to stand on two legs like a regular man.
- Selkies and Wereseals: A magical seal than can turn into a human after shedding its seal skin.
- Skinwalker: A shapeshifting sorcerer from Navajo folklore, who can change between human and animal forms at will.
- Our Werewolves Are Different: Depictions of werewolves that differ from how fiction usually portrays them.
- Paradox Person
- Pattern-Coded Eggs: A fictional animal's egg matches the color and pattern of the animal inside it.
- Peeve Goblins: Creatures who exist to pester humanity with mundane inconveniences.
- Pegasus: A winged horse.
- The Phoenix: A mystical bird that ends its life by combusting into flames, before being reborn from its own ashes.
- Planimal: A hybrid creature that's both a plant and an animal.
- Plant Aliens: Extraterrestrial organisms similar to the plants of Earth.
- Plant Person: A sapient or anthropomorphic plant being.
- Cactus Person: An anthropomorphic cactus creature.
- Pumpkin Person: An anthropomorphic pumpkin creature.
- Treants: A tree-like humanoid creature.
- Prehistoric Monster: An ancient, gigantic creature that is (presumably) extinct.
- Primate Versus Reptile
- Proportionately Ponderous Parasites
- Psychopomp: A being who guides the souls of the dead to the afterlife.
- The Grim Reaper: A hood-wearing, skeletal being who personifies Death in Western folklore.
- Shinigami: A Japanese version of the Grim Reaper.
- Pun-Based Creature: Creatures based off of wordplay.
- Riddling Sphinx
- Roc Birds: Predatory birds of immense size, originating in Arabic folklore.
- Rock Monster: A living creature made of stone.
- Rodents of Unusual Size: Giant rats, mice, and other rodents.
- Sand Worm
- Sea Monster: Gigantic aquatic creatures that lurk around in lakes, rivers, seas, and oceans.
- Giant Enemy Crab: An enormous crab, lobster, or other crustacean.
- Kraken and Leviathan: Humongous cephalopods that are capable of bringing down ships and sailors with their tentacles.
- Sea Serpents: Large aquatic creatures with snakelike bodies, including overgrown eels.
- Stock Ness Monster: The legendary Loch Ness Monster and similar lake creatures.
- Turtle Island: A huge sea turtle that is big enough that its shell is mistaken for an island.
- Silicon-Based Life: Alien organisms that have a radically different biochemistry from Earth organisms (unlike us, they're not carbon-based).
- Shedu and Lammasu: Bulls or lions with human heads and bird wings, originally from Mesopotamian myth.
- Single Specimen Species: A truly unique individual, there's no other organism of its kind.
- Sleep Paralysis Creature: A shadowy being associated with sleep paralysis and nightmares, who often sits on its victim's chest.
- Slime Girl
- Solar System Neighbors: Extraterrestrial organisms which live on the moons and planets surrounding Earth within the same solar system.
- Space Whale: A whale-like creature that lives in outer space.
- Starfish Aliens: Extraterrestrial species that are far more bizarre than anything from Earth.
- Swamp Monster: A monstrous creature that resides in a swamp.
- Talking Poo: A living being made of feces.
- Terrifying Tiki
- Things That Go "Bump" in the Night: Monsters hiding under your bed or in the closet.
- Thunderbird: A giant bird connected with storms, usually drawn from Native American Mythology.
- Tulpa: A being or entity that can come into existence through the power of human imagination.
- Ultimate Life Form
- The Undead: Dead people who have (sort of) come back to life, but not perfectly.
- Dem Bones: Living skeletons.
- Calacas: Skeletons who represent (un)dead people in Mexican culture, especially during the holiday of Dia de los Muertos (Day of the Dead).
- Frankenstein's Monster: A being made up of dead body parts sewn together, who has been brought to life through mad science.
- Ghost Pirate: Undead pirates who have returned from Davy Jones' Locker to continue pillaging the high seas.
- Mummy: A preserved corpse wrapped in bandages that has come back to life.
- Nazi Zombies: The deceased soldiers of Nazi Germany who have returned to continue fighting World War II.
- Non-Human Undead: Undead creatures that were not human when alive.
- Dracolich: Undead dragons.
- Raising the Steaks: Undead animals.
- Our Ghosts Are Different: Disembodied souls or spirits of dead people.
- Headless Horseman: A ghostly man without a head who rides a horse.
- Stringy-Haired Ghost Girl: An angry female ghost out for revenge. Mostly inspired by the Japanese onryō spirit.
- Our Ghouls Are Creepier
- Our Liches Are Different
- Our Vampires Are Different: Intelligent revenant/zombie-like beings with a literal thirst for blood.
- Chinese Vampire: The Jiangshi, a Chinese equivalent to Western vampire myths.
- Classical Movie Vampire: They tend to resemble Dracula himself.
- Dhampyr: A hybrid being born from the sexual union of a human and a vampire.
- Looks Like Orlok: Vampires who resemble Count Orlok.
- Our Wights Are Different
- Our Zombies Are Different: Walking corpses, which (usually) aren't very bright.
- Artificial Zombie: A zombie is intentionally brought to life through scientific means.
- Flesh-Eating Zombie: Zombies usually crave the flesh of living humans (especially their brains).
- Parasite Zombie: A parasitic organism that can turn people into zombie puppets.
- Plague Zombie: An infectious disease that can turn people into zombies.
- Revenant Zombie: A zombie that isn't just a mindless beast, and remembers who they were when they were alive.
- Technically Living Zombie: It looks like a zombie and acts like a zombie, but isn't actually undead.
- Voodoo Zombie: A zombie that has been reanimated and controlled by a sorcerer through voodoo magic.
- Undead Child: Dead children who have been turned into ghosts, vampires, or zombies.
- Dem Bones: Living skeletons.
- Unicorn: Fabled one-horned horses.
- Winged Unicorn: A unicorn with wings (or a pegasus with a horn).
- Valkyries
- The Virus
- Wendigo: A formerly-human monster that has been transformed after engaging in cannibalism, which has cursed them with an endless appetite for human flesh. They originated from Algonquin folklore.
- When Trees Attack: The trees are alive and want you dead.
- Winged Humanoid: A humanlike being with a pair of wings.
- Youkai: Various creatures from Japanese Mythology.
- Bakeneko and Nekomata: Cat-like youkai.
- Baku: A tapir-like creature that eats bad dreams.
- Gashadokuro: Giant skeletons made of the souls of mass death.
- Kamaitachi: A weasel-like creature with sickle-like claws that rides wind currents and cuts people.
- Kappa: A "river goblin" resembling a cross between a monkey and a turtle.
- Karakasa: An old umbrella come to life.
- Kitsune: Japanese Fantastic Foxes.
- Nue: A monstrous chimera/manticore-like beast that brings ill omen with it.
- Nurikabe: A living obstructive wall.
- Oni: Horned ogre-like humanoids.
- Onryo: A (usually female) Vengeful Ghost.
- Orochi: A giant, multi-headed snake or dragon.
- Raiju: The tiger/wolf/dog/racoon-dog perosnification of lightning.
- Shinigami: A spirit of death, not wholly unlike The Grim Reaper. A surprisingly recent addition.
- Tanuki: A real animal also known as the "raccoon dog", treated in mythology as a shapeshifting trickster.
- Tengu: Mountain-dwelling humanoids which either have long noses or resemble crows.
- Tsuchigumo and Jorogumo: Spider-youkai.
- Tsuchinoko: A stout little snake cryptid.
- Yuki-onna: A pale, snow spirit lady.
- Zashiki-warashi: A childlike spirit that should be cared for to keep the one's house in good fortune.
- Yowies and Bunyips and Drop Bears, Oh My: The assorted critters of Australian folklore and mythology.