I just joined Bon Bon Kakku!
It's similar to Spoonflower, except more competitive and more "artsy" which I prefer!
Submitting work is a little more tricky.
They have specific specs for each of the 3 files you have to submit
per design as well as specs for the original work
you must submit if you win.
You can only sell in their shop if you win, so game on!
Plus, one of the required submissions has to be
like the photos below. Which I love making because I get to see my work "up" and looking real!