This is a quickly designed wrist rest for the Keychron K15 Max keyboard. I scanned and traced the keyboard so it's not perfectly flush but it gets the job done. The FreeCAD file is included with this project (please improve and remix!).

Printed with PLA on a Bambu P1S. I used the cut tool and selected dovetail with a 0.1mm clearance to get this to fit on a single plate.

The holes in the bottom fit 13mm (1/2") rubber feet.

Also check out Tonymoro's model for a different style: https://makerworld.com/en/models/1019533-keychron-k15-pro-max-palm-rest#profileId-1000537