I created a replacement key for a soap dispenser, which has a proprietary shape, looking a bit like a three-pointed star, with blunt edges. It's the kind of wall-mounted dispenser that you'll find in schools, businesses, etc.

Prints flat without support. I used PLA.

I don't have the print any longer (so can't show any picture in real life :-( ). It has been in use by my friend for 2+ years, so seems solid!