What Other Game like DI would you Buy?

Definitely Dreamworks (and for that matter all the other major animation studios). Dragons belongs in Infinity, those figures would be SO great.
DC Comics for sure.
Nintendo (Aka Super Smash Bros with figures)
Harry Potter
Lord of the Rings
Game of Thrones
Power Rangers

Don't think any other franchise has the same vault to pick from as Disney, but I would buy figures/playsets from
Square Enix
Neil Gaimans Sandman
Any type of monster collection, Freddy Kruger, Hellraiser etc.
A few choise musicians
Big bang theory, x-files.