Hammerspoon - This is a tool for powerful automation of OS X.
dwm - dwm is a dynamic window manager for X. It manages windows in tiled, monocle and floating layouts. All of the layouts can be applied dynamically, optimising the environment for the application in use and the task performed.
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).
Optimist Prime Bot - Facebook messenger bot with voice recognition, NLP & more
SizeUp - SizeUp allows you to quickly resize and position your windows with keyboard shortcuts or a handy menu bar icon. Arranging windows on Mac OS X is tedious and imprecise.
i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.