How about the Justice League , you can have acquaman, thor, Hela, also you can add characters from other super heroes from movies, like captain america, batman,
you can also draw upon the rich mythology of each civilisation, like nordic mythology, hindu mythology, greek mythology, persian etc
you can find new spells, like acid rain, earthwuake, chemical blast, bunch of thorns, fireblast, blind an opponent, reduce speed/accuracy of an opponent. remove magic - removes all spells cast or have a spell like anti magic which means no spell will work on all allies