I use https://www.spectacleapp.com/ for keyboard based window management.

I use https://github.com/kasper/phoenix It's mostly just a javascript driven utility for managing windows, but it's really easy to bash together some nice tiling. I've got it set up for os-alt-ctl-numpad (5 is fullscreen, the ordinals are half screen, and 7,9,1,3 are quarters.) and os-alt-ctl-shift- numpad for a 3x3 grid... along with a bunch of other things i've defined.

I use Amethyst (https://github.com/ianyh/Amethyst) and cannot give it a stronger recommendation.

Divvy