List of legendary creatures (I)
- Iannic-ann-ôd (Breton) - Ghost of a drowned person
- Iara (Brazilian) - Female water spirit
- Ibong Adarna (Philippine) - Bird that changes color when it finishes a song
- Ichchhadhari Nag (Hindu) - Shapeshifting venomous snakes
- Ichimoku-nyūdō (Japanese) - One-eyed kappa from Sado Island
- Ichiren-Bozu (Japanese) - Animated prayer beads
- Ichneumon (Medieval Bestiaries) - Dragon-killing animal
- Ichthyocentaur (Greek) - Human-fish-horse hybrid
- Iele (Romanian) - Female nature spirits
- Ifrit (Arabian) - Fire genie
- Ijiraq (Inuit) - Spirit that kidnaps children
- Ikiryō (Japanese) - Can be considered a 'living ghost', as it is a person's spirit outside their body
- Ikuchi (Japanese) - Sea serpent that travels over boats in an arc while dripping oil
- Iku-Turso (Finnish) - Sea monster
- Il-Belliegħa (Maltese) - Malevolent well spirit
- Imp (Medieval) - Small demonic servant
- Impundulu (Southern Africa) - Avian, vampiric lightning spirit
- Imugi (Korean) - Flightless, dragon-like creatures (sometimes thought of as proto-dragons)
- Inapertwa (Aboriginal) - Simple organisms, used by creator-gods to make everything else
- Incubus (Medieval folklore) - Male night-demon and seducer
- Indrik (Russian) - One-horned horse-bull hybrid
- Indus Worm (Medieval Bestiaries) - Giant, white, carnivorous worm
- Inkanyamba (Zulu) - Horse-headed serpent
- Inugami (Japanese) - Dog spirit
- Ior (Romanian) - Giant creature, with good spirit
- Ipotane (Greek) - Two-legged horse-human hybrid, (as opposed to the four-legged centaur)
- Ippon-datara (Japanese) - One-legged mountain spirit
- Iratxoak (Basque) - Small demonic servants
- Irin (Jewish) - Fallen angels
- Ishigaq (Inuit) - Little people
- Island Satyr (Medieval Bestiaries) - Savage human-goat hybrid from a remote island chain
- Isonade (Japanese) - Shark-like sea monster
- Ittan-momen (Japanese) - Ghostly aerial phenomenon that attacks people
- Iwana-bōzu (Japanese) - Char which appeared as a Buddhist monk