Habitica - Habitica is a free habit building and productivity application.
Habit List - Create good habits and break bad ones with the app that keeps you focused.
When Did I…? - When Did I…?
Habio - Habio allows you to dive into the very nature of your habits through psychological exercises, CBT-based reflection journal and timely reminders adjusting to lifestyle goals.
Henry - Habits & Wellbeing - A new kind of productivity app focused on habits + wellbeing
Autohabit - Simple iOS app to develop good habits