Years ago (we’re talking decades) I ran into a small program that randomly generated raytraced images (think transparent orbs, lens flares, reflection etc), suitable for saving as wallpapers. It was a C/C++ program that ran on Linux. I’ve long since lost the name and the source code, and I wonder if there’s anything like that out there now?
I also thought it would be povray as this is what I was using on linux over two decades ago. Maybe this list could help you:
https://en.m.wikipedia.org/wiki/List_of_ray_tracing_software