Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Purp - A smart to-do list and goal tracker app
Any.DO - The #1 task management app used by over 11 million people globally, Any.do is your free mobile and online task manager for Android, iPhone, Web and more.
Things - Things is an easy to use task manager.
Microsoft To-Do - Task management tool
Nirow - Habit tracking: Automated, Siri-ed, Calendar-ed, and More!