There needs to be a Steven Universe RPG.

[Fish Salad]

Okay, that sounds stupid, but I mean one with like, a story that changes depending on your own choices, and you can make your own characters, and my god i think i've come up with the best idea ever for fanfic-ers.

[RokuroCarisu]

I remember seeing a Gem creator somewhere...
Also, there is always RPG Maker or D&D. Or, in fact, Tails of Equestria should lend itself pretty well to Steven Universe RP.

[Fish Salad]

No, a 3D video game. Also, Soundtrack Attack doesn't count.

[Sinzim]

I get what you mean, could be different types of gems you could create your character as, different classes, gear, leveling up and stats, all that kind of stuff