I modeled these to fit some wire shelves I have with 30mm tall shelf fronts with 6mm diameter wire on the top and bottom, which these clip on to.

They clip on fairly snugly and shouldn't move too much. I printed in PETG and they are strong enough for my use case of hanging laundry to dry. You may want to increase your perimeters so you don't get any infill when slicing.

I found a few similar hook designs on printables but I didn't see anything that fit this particular shelf's dimensions, so I made my own.

Link to the OnShape document: https://cad.onshape.com/documents/1b334fa10e0c06457ddde31e/w/509d78e30713e6f4a4e314a9/e/28dfb515daa5fe18d0d9b277?renderMode=0&uiState=6814db6c0437070bbca38f64