Todoist
Freemium
Todoist: To-Do list and Task Manager.
Task Coach
Open Source
A simple and friendly task manager written in Python.
Doit.im
Freemium
Doit.im is a Cross-platform Best Online GTD Service, which can sync with Phones.
Org-mode
Open Source
Org-mode is an Emacs Mode for Notes, Planning, and Authoring.
Taskwarrior
Open Source
Taskwarrior is an open-source, cross platform time and task management tool. It has a command-line interface rather than a graphical user interface.
Nitro
Open Source
Nitro is free open source task management software.
Conqu
Freemium
Conqu is a simple yet powerful task management tool designed to help you conquer your inbox and get things done.
Goalton.com
Freemium
Goalton.com is a platform for goal and task management.
Things
Commercial
Things is a delightful and easy to use task manager.
OmniFocus
Commercial
OmniFocus is a personal task manager.
TickTick
Freemium
TickTickis a cross-platform to-do list app & task manager helps you to get all things done and make life well organized.
Todo.txt
Open Source
todo.txt is software and operating system agnostic; it's searchable, portable, lightweight and easily Todo management software.
TaskPaper
Commercial
TaskPaper is a plain text to-do list that's surprisingly adept.
Tasque
Open Source
Tasque is an open source task management application.
Nozbe
Commercial
Nozbe is a to-do, task, project and time management application.
