[albertzeyer]

This guy (Phil Wang, https://github.com/lucidrains) seems to have the hobby to just implement all models and papers he finds interesting. See his GitHub page. He has 228 repos, and most of them are some implementation of some machine learning paper. Some of those repos are quite popular.

[jamessb]

The project README thanks "Stability.ai for the generous sponsorship to work and open source cutting edge artificial intelligence research", so it's not necessarily just a hobby (though it's possible they just provide compute resources).

Phil's homepage [1] links to a form [2] where you can suggest a paper for him to implement.

[1]: https://lucidrains.github.io/

[2]: https://forms.gle/Dtrxc6CceHEcqS6X6

[asciii]

He is open to consultation and work so the repo is a nice gallery of what's possible and learnable material

https://lucidrains.github.io/

He also is creator of ThisPersonDoesNotExist.com

[PartiallyTyped]

The implementation is quite clean too, and provided that you have read the papers, they are easy to understand.