Gone - An ephemeral to-do list

KosmoTime - The to do list with super powers

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

EveryPlan - Routines to promote wellbeing

Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX. 

Centered - Centered helps you get into a Flow State faster and stay there longer so you can do your best work.