I wanted a wrist rest for my 75% mechanical keyboard but didn't want to buy one. So, I modeled this (32.5 cm wide, 2 cm thick, 8 cm deep). Although it's too big to print in one piece on a Prusa MK4S, I provided a 3MF with a split version.
I've also included the Fusion360 file in case you wanted to customize it.
The author marked this model as their own original creation.