[girvo]

https://github.com/ianyh/Amethyst

This is what I used for years. Sadly I'm back in Windows land these days due to work.

[imawizard]

I‘m using Windows again as well (just loving the crap-/bloatware for corporate vpn, syncing powerpoint templates, group policies etc.) which is why I made a small window manager in AutoHotkey:

https://github.com/imawizard/MiguruWM

The wiki also contains a list of other window managers for Windows one might want to check out.