I love the Mini Drawers Ultimate tiny storage cabinets designed by zeropage (https://www.thingiverse.com/thing:1889761).

After printing a few, I wondered what else could attach using the interlocking system. A mini tool rack came to mind so I designed one using Tinkercad. It slides into the grooves on any of the "houses" from the Mini Drawers Ultimate.

It will hold a few hex wrenches, a small open end wrench and maybe a small screw driver.