vograce. stickerapp as well

I'll check those out, thanks!

Any opinions on Redbubble? I know it's a popular choice, but is there anything iffy I should be aware of?

Redbubble doesn't give you good profit at all. I think it's better to go ahead and try to run your own shop with shipping if you're only gonna do small things. I also have never understood the tagging system for redbubble. Many fan-made items I've made in the past for things like pokemon and such get taken down, yet so many other people will just straight up steal official vectors and get away with selling them.

Fourthwall, if you're a streamer, has better profits and has plenty of items to choose from for custom creations.