What if Thor appers in next Thor, Guardians of Galaxy , Spiderman or Dr Strange(would fit in perfectly)
Odins older Brother , Hela, Surtur or they all working together.
and more villians and heroes like we got in other marvel movies already,
Enchantress and Executioner could be good and powerfull minions
also Malekith and the casket of eternal winter and ice elfs would work all great together.
Dr Strange, Thor and Ironman would be great in a cross over.
Dr Strange has a villian Nighmare that could be used too in some ways?