I wished to hang some model rocket airframe (body) tubes to the sides of my existing wire frame shelves. I designed a simple hex frame with a clamp that clips on the wire frame. The shelf unit is from a home improvement store. 

The shelf top to bottom width was measured at 29.28 mm. This is what the “clamp” is based on.  It can be flipped around for either side of the shelf frame system. Pretty simple and a quick print. I printed these in PLA at 0.3 mm resolution on my PRUSA MK3S+. 3mf file is provided to scale or customize for your needs.