Gone - An ephemeral to-do list

Runway - A free, visual tool to help startup founders understand, manage and extend their cash runway.

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

Cushion - A forecasting app for freelancers, get better insights

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

Profly - Profly doesn't judge you by your expenses.