AquaSnap - Too many windows on your screen? Stop wasting your productivity.
Preme for Windows - Speeds up your window switching.
Mizage Divvy - Divvy is an entirely new way of managing your workspace.
Rectangle - Window management app based on Spectacle, written in Swift.
Moom - Move your mouse over the green zoom button in any window, and Moom's mouse control overlay will appear (as seen in the above animation).
altdrag - AltDrag allows you to move and resize windows much easier.