This mount can be clipped onto a Skadis pegboard. The raspberry pi (all versions) can be screwed into the mount. M2.5 self tapping works best but M3 should work with some care as well. You can also tweak the model in Onshape: link

Print Instructions

Print without supports. PLA works just fine. If you intend to unclip it often, aim for PETG or ASA/ABS. layer height 0.2 is best for visual quality but anything will do.

Onshape document: link