Gone - An ephemeral to-do list
i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
Streaks - The to-do list that helps you form good habits.
awesome - A dynamic window manager for the X Window System developed in the C and Lua programming languages.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
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.