This is just a very simple hook I tossed together to hang from a wire shelf.  The original reason was to have a hook large enough that my daughter could hang her tennis racquet on the side of her shelf, but they turned out pretty handy for a bunch of things, so I've ended up making quite a few.  The upper hook portion is suitable for wire up to 3/8" (9.5mm) in diameter, and the hook portion to hold the item is 1.5" (38mm) deep.  

I printed this in PETG with three perimeters and 20% infill, I think I'll bump the perimeter count up a bit for the next batch I do, I might suggest four or five perimeters, just for the extra strength.