Vise grip pliers hanger for french cleat wall with a depth of 15mm. Even pliers with rubber coated handles (from for example https://www.hbm-machines.com/nl/p/hbm-16-delige-griptangenset should fit except the 4 top/biggest ones).

Versions

There are 2 versions, one flat and one with a 3 degrees of tilt. The tilt version may be a little too thick with the screw all the way in.

Printing

You should be able to print it without support upside down so with the top flat on the bed. I've printed them with regular PLA, 3 wall layers and an infill of 25% and I haven't had any problems so far.

Remixing

The model was made with OnShape and should be available to all https://cad.onshape.com/documents/5d6f040f905bc86da2ecab88/w/341c4a905c907bbc0980aabd/e/8771dfa5d2c418e8a77b21c8

The cleat configuration is in the first tab (on the bottom), the settings per model are in the part studio itself in a folder called variables.