Habitica - Habitica is a free habit building and productivity application.
ProductiveApp.io - Productive is a habit tracking application.
LifeRPG - Automatically prioritize your goals and gain XP for achieving them. Features:
Streaks - The to-do list that helps you form good habits.
Coach.me - Coach.me is a coach that goes everywhere with you, helping you achieve any goal, change any habit, or build any expertise.
Strides - Track all your goals & habits in one place, with flexible reminders to hold yourself...