Thought I might contribute with something in return for all your help and giving me RetroArch.
This is a modified older shader from Harlequin presented to me by hunterk. It’s modified so you can easily change colors in the Virtual Boy core simply by changing palettes.
These are just a couple of palettes, some made by Harlequin and some made by me:
This is how it looks when applied:
Everything that is needed is attached in this post, it’s never been easier to change colors in Virtual Boy so enjoy!