Things - Things is an easy to use task manager.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Everlist Task Manager - Groceries, trips, errands, and daily todos managed simply. get your tasks under lovely control.
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.
Llama Life - Say goodbye to never-ending lists, and hello to daily bliss
Microsoft To-Do - Task management tool