Everyday - Take a photo of yourself everyday.
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.
Coach.me - Coach.me is a coach that goes everywhere with you, helping you achieve any goal, change any habit, or build any expertise.
Habitify - The easiest way to keep track of your habits
SuperBetter - Empower youth mental health through schools and sports