What other genderfluid deities are there besides Loki?
Dionysus!
Also most kemetic deities have male/female counterparts or aspects, or are portrayed with male/female characteristics (like male deities with breasts).
Amun and the Ogdoad are good examples, and i believe Amun has an epithet related to genderfluidity unless i’m remembering incorrectly (something along the lines of Great He-She?)
Shai, the egyptianis god of fate and destiny, is also genderfluid! as a woman, Her name is Shait. a good chunk of the Netjer have male/female counterparts who stand as Their own beings, but Shai and Shait are the same deity, just different genders.