- Á Bao A Qu (Malay) – Entity that lives in the Tower of Victory in Chitor.
- Aatxe (Basque) – Bull spirit.
- Abaasy (Yakuts) – Iron-toothed demons.
- Abada (African) – Unicorn that inhabits the African Congo.
- Äbädä (Tatar) – Forest spirit.
- Abaia (Melanesia) – Huge magical eel.
- Abarimon (Medieval Bestiaries) – Savage humanoid with backward feet.
- Abath (Malay) – One-horned animal.
- Abura-sumashi (Japanese) – Creature from a mountain pass in Kumamoto Prefecture.
- Acephali (Greek) – Headless humanoids.
- Acheri (Hindu) – Disease-bringing ghost.
- Achiyalabopa (Pueblo) – Huge bird god.
- Achlis (Roman) – Curious elk.
- Adar Llwch Gwin (Welsh) – Giant birds that understand human languages.
- Adaro (Solomon Islands) – Malevolent merfolk.
- Adhene (Manx) – Nature spirit.
- Adlet (Inuit) – Vampiric dog-human hybrid
- Adroanzi (Lugbara) – Nature spirit.
- Adze (Ewe people) – African vampiric-forest being.
- Aerico (Greek) – Disease demon.
- Æsir (Norse) – Norse deities.
- Aeternae (Greek) – Saw-horned monster.
- Afanc (Welsh) – Lake monster (exact lake varies by story).
- Agni (Hindu) – God of fire and sacrifices.
- Agathodaemon (Greek) – Spirit of vinefields and grainfields.
- Agloolik (Inuit) – Ice spirit that aids hunters and fishermen.
- Agogwe (East Africa) – Small, ape-like humanoid.
- Akhekh (Ancient Egypt) - Oryx-Bird hybrid that brings chaos.
- Ahkiyyini (Inuit) – Animated skeleton that causes shipwrecks.
- Ahuizotl (Aztec) – Anthropophagous dog-monkey hybrid.
- Ahura (Zoroastrianism) – Zoroastrian spirits.
- Aigamuxa (Khoikhoi) – Anthropophagous humanoid with eyes in its instep.
- Aigikampoi (Etruscan) – Fish-tailed goat.
- Airavata (Hindu) – Divine elephant.
- Aitu (Polynesian) – Malevolent spirits or demons.
- Aitvaras (Lithuanian) – Household spirit.
- Ajatar (Finnish) – Dragon/snake female spirit, is said to spread diseases
- Akateko (Japanese) – Tree-dwelling monster.
- Akhlut (Inuit) – Orca-wolf shapeshifter.
- Akka (Finnish) – Female spirits or minor goddesses.
- Akki (Japanese) – Large, grotesque humanoid.
- Akkorokamui (Ainu) – Sea monster.
- Akuma (Japanese) – Evil spirit or devil
- Akupara (Hindu) – Giant turtle that supports the world.
- Akurojin-no-hi (Japanese) – Ghostly flame which causes disease.
- Al (Armenian and Persian) – Spirit that steals unborn babies and livers from pregnant women.
- Ala (Slavic) – Bad weather demon.
- Alal (Chaldean) – Queen of the full moon.
- Alan (Philippine) – Winged humanoid that steals reproductive waste to make children.
- Alce (Heraldic) – Wingless griffin.
- Aleya (Bengali) – Spirit of a dead fisherman.
- Alicanto (Chilean) – Bird that eats gold and silver.
- Alicorn (Bestiario medieval) – Winged unicorn.
- Alkonost (Slavic) – Angelic bird with human head and breasts.
- Allocamelus (Heraldic) – Ass-camel hybrid.
- Almas (Mongolian) – Savage humanoid.
- Al-mi'raj (Islamic) – One-horned rabbit.
- Aloja (Catalan) – Female water spirit.
- Alom-bag-winno-sis (Abenaki) – Little people and tricksters.
- Alp (German) – Male night-demon.
- Alphyn (Heraldic) – Lion-like creature, sometimes with dragon or goat forelegs.
- Alp-luachra (Irish) – Parasitic fairy.
- Al Rakim (Islamic) – Guard dog of the Seven Sleepers.
- Alseid (Greek) – Grove nymph.
- Alû (Assyrian) – Leprous demon.
- Alux (Mayan) – Little people.
- Amaburakosagi (Japanese) – Ritual disciplinary demon from Shikoku.
- Amala (Tsimshian) – Giant who holds up the world.
- Amamehagi (Japanese) – Ritual disciplinary demon from Hokuriku.
- Amanojaku (Japanese) – Small demon.
- Amarok (Inuit) – Giant wolf.
- Amarum (Quechua) – Water boa spirit.
- Amazake-babaa (Japanese) – Disease-causing hag.
- Amemasu (Ainu) – Lake monster.
- Ammit (Ancient Egyptian) – Female demon who was part lion, hippopotamus and crocodile and devoured the souls of the wicked.
- Amorōnagu (Japanese) – Tennyo from the island of Amami Ōshima.
- Amphiptere (Heraldic) – Winged serpent.
- Amphisbaena (Greek) – Serpent with a head at each end.
- Anak (Jewish) – Giant.
- Andean wolf (Argentina) – Mountain wolf
- Androsphinx (Ancient Egyptian) – Human-headed sphinx.
- Angel (mainly Christian, Jewish, Islamic traditions) – Divine beings of Heaven who act as mediators between God and humans; the counterparts of Demons.
- Anqa (Arabian) – Giant mythical female bird similar to a phoenix.
- Ani Hyuntikwalaski (Cherokee) – Lightning spirit.
- Ankou (French) – Skeletal grave watcher with a lantern and scythe.
- Anmo (Japanese) – Ritual disciplinary demon from Iwate Prefecture.
- Antaeus (Greek) – Giant who was extremely strong as long as he remained in contact with the ground.
- Anubis (Ancient Egyptian) – God of funerals
- Antero Vipunen (Finnish) – Subterranean giant.
- Anzû (Sumerian) – Divine storm bird
- Ao Ao (Guaraní) – Anthropophagous peccary or sheep.
- Aobōzu (Japanese) – Blue monk who kidnaps children.
- Apkallu (Sumerian) – Fish-human hybrid that attends the god Enki.
- Apsaras (Buddhist and Hindu) – Female cloud spirit.
- Aqrabuamelu (Akkadian) – Human-scorpion hybrid.
- Arachne (Greek mythology) - Centaurid, human-spider hybrid.
- Ardat-lilî (Akkadian) – Disease demon.
- Aralez (Armenian) – The oldest gods in the Armenian pantheon
- Argus Panoptes (Greek) – Hundred-eyed giant.
- Arikura-no-baba (Japanese) – Old woman with magical powers.
- Arimaspi (Greek) – One-eyed humanoid.
- Arion (Greek) – Swift green-maned talking horse.
- Arkan Sonney (Manx) – Fairy hedgehog.
- Asag (Sumerian) – Hideous rock demon.
- Asakku (Sumerian) – Demon.
- Asanbosam (West Africa) – Iron-toothed vampire.
- Asena (Turkic) – Blue-maned wolf.
- A-senee-ki-wakw (Abenaki) – Stone giant.
- Ashi-magari (Japanese) – Invisible tendril that impedes movement.
- Asiman (Dahomey) – Vampiric possession spirit.
- Askefrue (Germanic) – Female tree spirit.
- Ask-wee-da-eed (Abenaki) – Fire elemental and spectral fire.
- Asobibi (Japanese) – Spectral fire from Kōchi Prefecture.
- Aspidochelone (Medieval Bestiaries) – Island-sized whale or sea turtle.
- Asrai (English) – Water spirit.
- Astomi (Greek) – Humanoid sustained by pleasant smells instead of food.
- Asura (Hindu) – Hindu malevolent divinities.
- Aswang (Philippine) – Carrion-eating humanoid.
- Atomy (English) – Surprisingly small creature.
- Ato-oi-kozō (Japanese) – Invisible spirit that follows people.
- Atshen (Inuit) – Anthropophagous spirit.
- Augerino (American) - Subterranean creature.
- Auvekoejak (Inuit) – Furry merman.
- Avalerion (Medieval Bestiary) – King of the birds.
- Awa-hon-do (Abenaki) – Insect spirit.
- Axex (Ancient Egyptian) – Falcon-lion hybrid.
- Ayakashi (Japanese) – Sea serpent that travels over boats in an arc while dripping oil.
- Ayakashi-no-ayashibi (Japanese) – Spectral fire from Ishikawa Prefecture.
- Aziza (Dahomey) – Little people that help hunters.
- Azukiarai/Azukitogi (Japanese) – Spirit that washes azuki beans along riversides.
- Azukibabaa (Japanese) – Bean-grinding hag who devours people.