Simple hook i made to fit Rubbermaid “Shelf” (pic of label is included). The model i fit this to is SKU FG4B8100WHT. Model provided has a hook length of 80mm but this could easily be tweaked. OnShape document is here.

Lay on its side, print it. I used PETG 15% crosshatch infill, 3 walls. Strengthen as needed to suite your use case.