Habitica - Habitica is a free habit building and productivity application.
Everyday - Take a photo of yourself everyday.
Do It Now - Do It Now is a great mobile app that helps you to create new habits and maintain focus on your goals.
Habit List - Create good habits and break bad ones with the app that keeps you focused.
myPoli - Gameified to-do list and habit tracker.
Habitify - The easiest way to keep track of your habits