Things - Things is an easy to use task manager.
Flux - Application Architecture for Building User Interfaces
Everlist Task Manager - Groceries, trips, errands, and daily todos managed simply. get your tasks under lovely control.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Todoist 10 for iOS - A completely new Todoist for iOS