Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4941921.
EDIT: I realized my design only worked in a horizontal direction and not a vertical one. I therefore redesigned it to work vertically, have a bit more friction, and minimize the amount of material needed.
This is designed to hold your XChange tool plates, allowing you to mount them in a variety of positions. The tolerances hold the tool plate by the pins fairly securely so they shouldn't fall out if bumped. There are two versions, one has M3 socket holes to mount to a piece of 2020 extrusion, the other has countersunk holes for screws to mount to wood. The pictures have mounting holes only in one direction, but the uploaded version has mounting holes in both directions. I printed with four wall layers for a bit more strength, but not sure if that's actually needed.
Inspired by Woodwaker's design.