A single keycap version of the Galactic Empire and Rebel Alliance sets that goes over the number pad. These work on the Logitech G-610 and a Corsair keyboard in my house, but they should fit some other mechanical keyboards. Both keyboards have a brown cross under the keys that these go on. You can print the insert and check to see if it fits your keyboard before printing the keycap.
Print one insert for each keycap you print. The keycaps should be printed in black PLA. The inserts are thin to allow light to shine through. You can print these in white/translucent and then change the color on your keyboard (if you have that option), or you can print them in colored PLA. The colored filament may be a bit dimmer depending on the color. I used red and blue filament for the picture.
Printing: I printed at .12mm layer height, 3 wall count and 20% infill.
Placing the inserts: Make sure the inserts are aligned properly in the keycap. They should be aligned so the long part is on the x axis (horizontally) in the cap. There is a small ridge on 2 of the sides on the inside of the cap that the insert needs to get past. I've been carefully using a flat-head screwdriver to push straight down on the sides of the insert until it snaps into place. For some of the inserts I had to push at several spots to get it to snap in all the way. Stear clear of the cross in the middle, or you may break it.
*This Design was made in Tinkercad from the ground up. I've made the blank keycap and insert public for anyone who wants to make something with it. Link is here: https://www.tinkercad.com/things/fNe72qQclrM
The author marked this model as their own original creation.