Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Binery.co - BINERY powers the financial back office for startups and small businesses. We provide a real-time and seamless bookkeeping experience for growing businesses in Asia and beyond!
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
WeekToDo - Free and Open Source Minimalist Weekly Planner and To-Do list App Focused on Privacy
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.