When starting from scratch with an electronics problem  often do the proof of concept stuff on a breadboard.  When I do that kind of work I like t to be right in my face, which it exactly is providing I put it in the Panavise in the middle of my workbench.  However - breadboards have unfortunate protrusions on the side that make clamping it in there difficult and leave it unstable.

This model provides an “adapter” for that purpose.  I've included the FreeCAD file so if you want to make other ones you have a starting point.  I did not spend a lot of time on this - the model is not parametric, but it's simple enough.  

Just print this and push the breadboard into it & you're good to go.