Wire rack shelving clips

I looked in all the wrong places because I never found a clip I'd be satisfied with for wire racks and hanging stuff from the edge.  These clip to the edge of the wire racks in my current and previous house, so I think they are standard for at least US big box hardware stores.  I then CA glued some hangers for filament spools.  If there's enough interest, I can post the model for the spool hangers as well.