I had one successful shop, it wasn't making me rich but it was working. After a few months, while I was buying some more designs, I had the feeling the authors weren't selling me all the licenses I needed to resell the images as they said. So I shut down the whole shop and related social media profiles before getting in some trouble.
I now have a shop on Redbubble under my name but I have just started it and I'm not expecting to make money from it because it's a kind of experiment. I'm not niching down this time, the shop on Teespring was about yoga.
You can reach out to me on Twitter ;)