i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
Headspace - Meditation made simple. Brilliant things happen in calm minds.
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.
Meditation Studio - Curated collections of guided meditations
Openbox - Openbox is a highly configurable, next generation window manager with extensive standards support.
Calm - Calm.com can help you reduce stress and increase calm.