Gone - An ephemeral to-do list
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX.
LightShot - The fastest way to take a customizable screenshot.