Habitica - Habitica is a free habit building and productivity application.
Everyday - Take a photo of yourself everyday.
Loop Habit Tracker - Loop Habit Tracker (AKA uhabits) helps to create and maintain good habits in order to achieve their...
Habitify - The easiest way to keep track of your habits
Google Calendar - Spend less time managing your day & more time enjoying it
Habit List - Create good habits and break bad ones with the app that keeps you focused.