Habitica - Habitica is a free habit building and productivity application.
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.
Gone - An ephemeral to-do list
Loop Habit Tracker - Loop Habit Tracker (AKA uhabits) helps to create and maintain good habits in order to achieve their...
The ToDon't List - A to-do list for avoiding the things you shouldn't be doing