2Do lets you take a completely different approach to managing your tasks. With its extremely simple-to-use interface.

Awesome notes is a powerful text and voice note taking application with many great features.

Clear is a tasks, reminders and To-Do lists app.

Doit.im is a Cross-platform Best Online GTD Service, which can sync with Phones.

eXtrigo is a knowledge-based online community.

footnote is a very light and neat Notebook App for elementary OS.

Avaza is a beautiful online software suite with modules for Project Management, Timesheets, Expenses & Invoicing. Access from anywhere, with any device.

buckets.co helps you optimize workflows & collaboration at all levels.

Conqu is a simple yet powerful task management tool designed to help you conquer your inbox and get things done.

EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries, e…

FCorp My Calendar is a free software to manage a diary, notes, schedules, birthdays, etc.

Google Tasks is the task list functionality provided by Google.