Reported by Tomxp411 on the community forum via private message:

Also, there's a good source for key stickers online. Amazon has both black and white key stickers, and they're a vinyl-like product that is pretty durable and can even be removed and re-applied. I've got two sets now; one is on my Coolermaster keybard, and the other is just sitting under my monitor for visual reference (I just look at that, rather than my hands.)

Here's one example: www.amazon.com/COMMODORE-NON-TRANSPARENT-KEYBOARD-STICKERS-BACKGROUND/dp/B000ZXOUB2/ref=sr_1_1?ie=UTF8&qid=1524815680&sr=8-1&keywords=commodore+64+stickers

4Keyboards Commodore keyboard stickers page:

https://www.4keyboard.com/336-commodore-keyboard-stickers

Those examples are of aesthetic value primarily, but could fit other purpose.

Ready made found here:

• http://www.mateoproceo.com/

Custom stickers:
This site is known of unixstickers, made for keyboards and various cases:

• https://www.stickermule.com/

Retrobiker from the community forum shared a set of keyboard stickers he made for his keyboard, showing all the special keys (run/stop, restore, clr/home, commodore logo, etc) and also the petscii graphic characters.

But the links don't seem to work anymore so here they are again:

The stickers are available here:

• https://drive.google.com/open?id=1ExPlVvRYnlFVKDo-UzQ2t3Ws-4D0zf4D

Here's a photo of how he placed them on his keyboard:

• https://drive.google.com/open?id=1C-Q9JYkAehZ3QOGXtbm4qMwHIRZtGQ4O

Here are the related forum threads:

• https://gurce.net/oldforum/168-keyboard-stickers.txt
• https://gurce.net/oldforum/217-the-joystick-is-a-copy-of-the-competition-pro-5000.txt