I know that there is already a Frozen fandom [unless it counts as Disney] and The Lion King fandom [unless its Disney]
And also a Brony/MLP fandom, and Furry Fandom.
And also a Cryptid fandom. [Cryptids are monsters] UNLESS thats Creepypasta, but Creepypasta are stories that do not exist, and Cryptids are monsters that MAY exist...