These are simple holders for MT2 and MT3 tools. Both models use #8 screws to mount to a workbench or piece of wood. STEP files are included.

These are based off of this original design by CABTinker on thingiverse. I've added the missing internal taper and added a MT3 version. The original can be found at https://www.thingiverse.com/thing:3482126.
 

I have printed these in PLA with 15% infill and 3 perimeters and they seem very sturdy.