This is a 3D printable replacement for the plastic hooks that hold a rod under the type of wire shelves used in all our closets. The original part is surprisingly sturdy, but it is very easy to put a lot of weight on the rod, and we've had a few snap off the little piece in the front that locks over the front of the shelf wire. The cover photo shows the failed part, an intact original, and my 3D-printed replacement. The second photo shows an intact original part in use.

Printed out of PLA at 0.24mm with 3 wall loops and a 15% hex infill pattern with no top or bottom layers, my replacement is much lighter but at least as strong as the original. The lip that failed on the original part can't fail here without tearing the extruded pla and the hex infill pattern adds rigidity and acts as a bit of a shock absorber preventing deformation that could lead to failure. The outline of my part is almost identical to that of the original and it installs the same way, but I also slightly beefed-up the area above the rear part that holds on to the wire horizontally.