Purp - A smart to-do list and goal tracker app
Habitica - Habitica is a free habit building and productivity application.
Nirow - Habit tracking: Automated, Siri-ed, Calendar-ed, and More!
When Did I…? - When Did I…?
Things - Things is an easy to use task manager.
Habit List - Create good habits and break bad ones with the app that keeps you focused.