Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists. It is designed for composite tasks, and also offers effort tracking, categories, notes and more.
MyLifeOrganized (MLO) is a personal task outliner and to-do list manager which will help you to organize your goals, projects and tasks into a tree.
The powerful, full-featured Personal Information Manager for Windows offering Email, Synchronization, Portability, Network support, Android and iOS versions.
Lifestyle Inspector is a free windows GTD/productivity/todo-list app with integrated Mind-mapping and powerful personal productivity reports.
ThinkingRock open source and multi-platform software for Getting Things Done - the stress-free productivity methodology and international best selling book by David Allan. [ http://en.wikipedia.org/wiki/Getting_Things_Done ]
Natara Bonsai is a Palm OS and Windows Mobile outliner application with a Windows desktop client that also works as a full-featured standalone outliner and task manager. The Bonsai 5 Desktop Edition offers multiple views of a hierarchical outline: single-, dual- or triple-pane...
Official site inaccessible, but app still available on download sites.
Wieldy is a free to-do list manager that is based on the principles of GTD (Getting Things Done). It allows you to manage your to-dos in a simple but effective way. To-dos can be created as thoughts and actions, which can then be assigned to the Next Action, Today, or Someday...
All-in-one organizer - integrates all your PIM needs in the well-organized interface: to-do list management, time planning, contacts, reminders, recurring options and notes. Portable software.Discontinued
Last updated in March 2013.