Endcaps for wire shelving

thingiverse

We have some of those ubiquitous enamel-coated wire shelves in a couple of our closets - and ours have a space on each side where if you place a hanger there, it can get shoved off the end of the shelf. These are made to very securely snap onto the shelf. I haven't even had to glue them - they're just that secure. You may need to adjust the print settings a little to get them to work on yours.