HHTWM
I've built my own window manager for macOS that gives me layout-based automatic tiling.
Not having to think about placing windows on the screen, and having everything always visible, has been a huge boost for me.
HHTWM is library with small API to be used within larger Hammerspoon ↗ configuration.
It's open sourced and well documented: szymonkaliski/hhtwm ↗.