Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Notesnook - Notesnook is a simple and private note taking app that keeps your notes organized and synced on your phone, tablet and computer.
doo - A smart, simple app for reminders and to-dos
UpNote - A beautiful and clean cross-platform app for notes organizer
Simplenote - The simplest way to keep notes. Light, clean, and free. Simplenote is now available for iOS, Android, Mac, and the web.
todoZero - A powerful to-do and note app for busy people.