I didn't find any guitar rings anywhere. So here is my design. 100% scale is size 50 (EU ring size). Scale as you need. I found out it is better to print flat on the tip. Does not scrape strings. Print with supports on the pad for better stability. Requires a bit of filing to get smooth surface.
I posted version 2:
https://www.printables.com/cs/model/422205-customizable-guitar-finger-pick-ring-pick-v2kytaro
The author marked this model as their own original creation.