Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
1st things 1st - Strategic prioritizer that helps you make up your mind.
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.
Gone - An ephemeral to-do list
Microsoft To-Do - Task management tool
Prioritize - Visualize tasks on different priority boards