I designed this rack to hold a 10 piece set of Bondhus T handle wrenches (from 3/32" to 3/8") on the side of a shelving unit, sized as large as I could fit on the bed of my Mini. It will hang over any piece of sheet metal up to about 1.5mm thick with at least 11mm of space behind.

Print this model with the top surface down, no supports. I used generic PLA with 3 perimeters of 0.8mm, which feels like overkill now that I have it installed and filled with wrenches, you may be able to get enough strength with two 0.6mm perimeters on a 0.4mm nozzle. Some infill is needed, but it isn't critical, 15% density of whichever pattern you like should be fine (I configured the attached 3mf for minimum print time.)