This small Carabiner can be used to replace or in combinations with split rings on keychains. I usually print a batch and then can easily replace one if it breaks. I'm sure that there are many other uses and can be scaled up if needed. print it out and the flip the clasp and it will hold surprisingly well.

I just needed a way to attach my shower scrubber to the wall. I had some of these cheap suction cups so after a couple of iterations made this design that is simple and stable and looks nice.