Gone - An ephemeral to-do list
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Streaks - The to-do list that helps you form good habits.
doo - A smart, simple app for reminders and to-dos
Simplenote - The simplest way to keep notes. Light, clean, and free. Simplenote is now available for iOS, Android, Mac, and the web.
Taskade - Make lists, organize your thoughts, and be inspired to get things done. Taskade is a collaborative space for your tasks.