Not pretty, but functional!

Underdesk Wireless Keyboard Mount to get your keyboard off the desk when you don't need it.  Mounted with double sided tape, but could drill out holes and add screws if extra support is needed.  

Left and right sides mount separately so can be adjusted to any length of keyboard.  Depth will accommodate keyboards up to 138mm.  Height will accommodate keyboards up to 42mm thick.

Printed on Bambu Lab X1 Carbon with Bambu Labs Black PLA Basic.

.2mm Layer Height, 3 Wall Loops, 20% Gyroid Infill (my preferred infill), Printed vertically with the back on the bed (side with the stopper nubs), used 2 skirt loops to ensure bed adhesion.