Wait! I got a different idea for a devil fruit; a trading card themed one. similar to the the Pasa Pasa no Mi, The Card Card Fruit would allow the user to turn their body into cards. They could also create cards of varying sizes that would be able to store various things from. Once somethings been stored, it can be released at any time in a different manor depending on what was stored. At first it would only be objects, but then he would learn to store more abstract things like abilities, techniques, and even knowledge. 

If Kuma could 'push' someone pain out of their body, then I'm pretty sure that I would be able to get away with storing more abstract things