Streaks - The to-do list that helps you form good habits.
Google Calendar - Spend less time managing your day & more time enjoying it
Taskful - Deadlines, meet your match.
Jorte - Schedule books must be practical and has a good design.
ToDoList - Windows desktop application to stay on top of your daily tasks.
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.