*UPDATED. Use the v4 files. They make the sides flat so that they can be printed vertically which gets rid of the banding you see in my original photos. Also works well with TPU and low infill (about 5-10%) in order to make them 'squishy'. The photo of the red one was printed vertically in a transparent TPU. The bands you see in it are actually the internal supports.
Custom wrist rests that I designed for the dactyl manuform 5x6 keyboard. They might work for the 6x6 as well, but not sure of the dimensions of the 4x5. Could just print one layer to find out.
See more info about building your own keyboard here:
I recommend printing with the filament color you hate the most, and then covering it in plastidip as it gives it a nice rubber texture.
I'm currently also attempting to print this in TPU, but not sure how that will work out.. definitely is going to take a long time though.
Plastidip works well to give it a more rubber feel instead of hard plastic. Could also just use stick on foam pads.