Here are some ideas that I thought of for some possible sets
Viewtiful Joe -Plenty of heroes and villains from this series. Lots of options for duo and giant figures (Joe and Silvia, Fire Leo and Frost Tiger, Big John, King Blue etc..)
Heroes- I think it would be pretty cool to have a Hiro Nakamura with the kensei sword clix :D
Death note- Weird yes, but a clix of L or Light would be pretty sweet
A set based on the Marvel vs Capcom series - A great series loved by fans I think it could translate well to clix (since half of the series is marvel lol). Plus duo figures like Ryu and Wolverine and Dante and Deadpool would be awesome.