The update the the Transmogrification option in the wardrobe allows players to equip skins as long as they have level 10 mastery of that race unlocked; however, there isn’t an option to unlock this feature for the avatars. It would be cool if this was a potential unlock for gate of the gods for killing the gods 10 times.
Also, as a side note, it would be cool if you could fuse unlocked creature wardrobe options to make unique overworld sprites for your character. For example it may be possible to fuse lister and make him white with a blood diamond.