DC comics
I believe that since Telltale has already aligned themselves with Vertigo comics, which is affiliated with DC Comics, I think the next big move for them, after the Game of Thrones series is finished would be to create a game for the Justice League (Batman or Superman individually if preferred) I think it would probably shoot up their income in seeing how the individual decisions of Batman or Superman help create their persona and what helps lead their foes to becoming the dangerous villains we have come to know and love/hate.
Seeing how Batman unknowingly creates the Joker, how Superman drives Luther to hate him, what potential decisions or events drive the Justice League together to become a team, and the various timed events that come with crime fighting!!!!! Truly, with DC Comics, it's hard to go wrong!
Comments
If Telltale is able, they could probably make A LOT of money doing DC comic games.
There's already the Arkham series for Batman. I think a Superman game made by Telltale would be great. It would focus more on the hard decisions, rather than smashing shit and using Superman's whole arsenal of powers.