- Ba (Egyptian) – Soul of the deceased, depicted as a bird or a human-headed bird
- Baba Yaga (Slavic) – Forest spirit and hag
- Babi ngepet (Indonesia) – Monster boar
- Baccoo (Guyanese/Surinamese) – Malevolent little people
- Badalisc (Italian) – Goat-like creature from the southern central Alps
- Bagiennik (Slavic) – Malevolent water spirit
- Bahamut (Arabian) – Giant fish
- Bai Ze (Chinese) – Talking beast which handed down knowledge on harmful spirits
- Ba Jiao Gui (Chinese) – Banana tree spirit
- Bak (Indian) – Assamese shape-shifting aqueous creature
- Bake-kujira (Japanese) – Ghostly whale skeleton that drifts along the coastline of Shimane Prefecture
- Bakeneko (Japanese) – Magical cat
- Bakezōri (Japanese) – Animated straw sandal
- Bakhtak (Iranian) – Night demon named Shaina
- Baku (Japanese) – Dream-devouring, tapir-like creature
- Bakunawa (Philippine) – Sea serpent that causes eclipses
- Balaur (Romanian) – Multi-headed dragon
- Baloz (Albanian) – Sea monster
- Bannik (Slavic) – Bathhouse spirit
- Banshee (Irish) – Screaming death spirit
- Baobhan Sith (Celtic Mythology) – Beautiful vampiric seductresses who prey on young travelers
- Bardha (Albanian) – Mountain spirit
- Bardi (Trabzon) – Shapechanging death spirit
- Barghest – Yorkshire black dog
- Bar Juchne (Jewish) – Gigantic bird
- Barnacle Geese (Medieval folklore) – Geese which hatch from barnacles
- Barong (Balinese) – Tutelary spirit
- Basajaun (Basque) – Ancestral, megalith-building race
- Baš Čelik (Serbian) – Powerful, evil winged man whose soul is not held by his body and can be subdued only by causing him to suffer dehydration
- Bashe (Chinese) – Elephant-swallowing serpent
- Basilisco Chilote (Chilota) – Chicken-serpent hybrid
- Basilisk (Italian) – Multi-limbed, venomous lizard
- Basty (Turkic) - Evil spirit or goblin of bad dreams
- Bathala (Philippine) – Primordial god of creation
- Batibat (Philippine) – Female night-demon
- Batsu (Chinese) – Drought spirit
- Baubas (Lithuanian) – Malevolent spirit
- Bauk (Slavic) – Darkness beast
- Baykok (Ojibwa) – Flying skeleton
- Beast of Bray Road (American Folklore) – Werewolf
- Beast of Gévaudan (France) – French werewolf
- Bean Nighe (Irish) – Death spirit; a type of Banshee/Bean Sídhe)
- Behemoth (Jewish) – Massive beast, possibly like a dinosaur or elephant
- Bendigeidfran (Welsh) – Giant king
- Bennu (Egyptian) – Heron-like, regenerative bird, equivalent to (or inspiration for) the Phoenix
- Berehynia (Slavic) – Water spirit
- Bergrisar (Norse) – Mountain giants who live alongside the Hrimthursar (lit. "Rime-Giants") in Jotunheim
- Bergsrå (Norse) – Mountain spirit
- Bestial beast (Brazilian) – Centauroid specter
- Betobeto-san (Japanese) – Invisible spirit which follows people at night, making the sound of footsteps
- Bhūta (Buddhist and Hindu) – Ghost of someone killed by execution or suicide
- Bi-blouk (Khoikhoi) – Female, cannibalistic, partially invisible monster
- Bies (Slavic) – Demon
- Bigfoot (American Folklore) – Forest-dwelling hominid cryptid.
- Binbōgami (Japanese) – Spirit of poverty
- Bishop-fish (Medieval Bestiaries) – Fish-like humanoid
- Biwa-bokuboku (Japanese) – Animated biwa
- Black Annis (English) – Blue-faced hag
- Black Dog (British) – Canine death spirit
- Black Shuck – Norfolk, Essex, and Suffolk black dog
- Blafard – Imaginary creature from the early United States of America
- Blemmyae (Medieval Bestiary) – Headless humanoid with face in torso
- Bloody Bones (Irish) – Water bogeyman
- Błudnik (Slavic) – Mischievous gnome
- Blue Crow (Brazilian) – Giant amazonian bird
- Bluecap (English) – Mine-dwelling fairy
- Bodach (Scottish) – Malevolent spirit
- Bogeyman (English) – Malevolent spirit
- Boggart (English) – Malevolent household spirit
- Boginki (Slavic) – Nature spirit
- Bogle (Scottish) – Malevolent spirit
- Boi-tatá (Brazilian) – Giant snake
- Bolla (Albanian) – Dragon
- Bonnacon (Medieval Bestiaries) – Bull-horse hybrid with flaming dung
- Boo Hag (American Folklore) – Vampire-like creature that steals energy from sleeping victims
- Boobrie (Scottish) – Roaring water bird
- Bozaloshtsh (Slavic) – Death spirit
- Brag (English) – Malevolent water horse
- British big cat (English) – mysterious black panther
- Brownie (English and Scottish) – Benevolent household spirit
- Broxa (Jewish) – Nocturnal bird that drains goats of their milk
- Bucca (Cornish) – Male sea-spirit, a merman, that inhabited mines and coastal communities as a hobgoblin during storms
- Bokkenrijders (Dutch) – Ghosts/devils riding flying goats; co-opted by bandits to instil fear during raids
- Bugbear (English) – Bearlike goblin
- Buggane (Manx) – Ogre-like humanoid
- Bugul Noz (Celtic) – Extremely ugly, but kind, forest spirit
- Bukavac (Serbia) – Six-legged lake monster
- Bunyip (Australian Aboriginal) – Horse-walrus hybrid lake monster
- Bunny Man (American Folklore) Virginia, Maryland, and Washington, D.C. Urban Legend – Spirit/Maniac that wears a bunny costume and wields an ax
- Bush Dai Dai (Guyanese) – Spirit that seduces and kills men
- Byangoma (Bengali) – Fortune-telling birds
- Bysen (Scandinavian) – Diminutive forest spirit
