Recently embraced the Gridfinity craze to organize my desk drawers.  I couldn't find a holder for my spare Logitech M310 mouse…so I made one.  Took the great SCAD file by @Jamie and made a template, then cut away the bits that I needed to.

It doesn't have magnet holes since I don't use them.

Printed in Elegoo Gray PLA.  .28 layer height though just about anything should work.