Gone - An ephemeral to-do list
UpNote - A beautiful and clean cross-platform app for notes organizer
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Notesnook - Notesnook is a simple and private note taking app that keeps your notes organized and synced on your phone, tablet and computer.
Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX.
todoZero - A powerful to-do and note app for busy people.