https://github.com/fogleman/primitive is a favorite of mine.

I don't know if it applies, but I post all my sketches on Github (but I use p5js, Javascript's Processing flavour): https://github.com/rberenguel/sketches

If you take a look at reddit.com/r/generative (and /r/proceduralgeneration) you can find interesting projects and ideas, and sometimes people also post their code.