He-man and Thunder cats would fit perfectly, Heman and Mun-ra could be Mythical champs adam support-He-man Atack, same for Mun-ra, Skeletor the free log champ, Teela(classic one of course) being the fusion and gorpo or man in arms a guaranteed, in thunder cats side Cheetara the login, Pantro the guaranteed, and Lion-O a Busted Void Lego fusion.
It's easy bro, hear me out. Teenage Mutant Ninja Turtles. Make them all affiliated with Lizardmen. Each turtle has a different affinity, you get a free one from login, you go for one from a fusion, go for one from a guaranteed. Plarium would be able to really bank on that.