Habitica - Habitica is a free habit building and productivity application.

LifeUp - A unique and highly customizable gamified to-do and habit-forming Android app: XP, attributes, gold, items, treasure chests, tomatoes to eat or sell, crafting, and even automation...

EpicWin - EpicWin is an iPhone app that puts the adventure back into your life.

Todoist - Todoist is a to-do list that helps you get organized, at work and in life.

Focumon - Gamify your daily goals!

Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.