I think adding different mythical creatures as skins to go on top of bezogies would be nice as the game progresses overtime. The skins could also bring special powers/moves and some skins could be specific to the world that you are in. Some examples could be:
Witches and Warlocks
Trees ( like “I am Groot”)
These could also be enemies and maybe after killing a specific enemy you collect a token, and once you have enough tokens of the enemy you can summon a skin of that enemy. And players trying to kill an enemy would have to race/fight to collect the skin token first.
These skins could also have customisable add-ons as well and colour variations that players can pick.