One of the best ways to do "artsy" that is, not main stream found on Amazon or some such is to travel. Go travel and don't go to the tourist typical spots, but go to various out of the way places. Ask locals to show you their wares or some "traditional" wares. Then you need to work out with them how you will buy and how you will ship. Not very easy, lots of work, but hay, if you want a niche that's not already taken, then that's what's needs to be done.