Does /co/ remember Fort Awesome? CN show that the network hated and cancelled ASAP? Turns out there were a bunch of unproduced episodes, and Ian JQ, the creator of OK KO posted two of his episodes on his channel, fully voice acted too.

https://www.youtube.com/watch?v=Dni1VYiVMxo
https://www.youtube.com/watch?v=B9skdG43W9s

Addtionally Audie Harrison has more storyboards, including another Uncle Grandpa episode
https://www.audieharrison.com/smfa-ego-maniacs-storyboard
https://www.audieharrison.com/smfa-sandwich-mountain-uncle-grandpa-storyboard