Doit.im - Doit.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Planisware Orchestra - Planisware Orchestra is a best-in-class project portfolio management software and solution, providing an agile approach to bring all the stakeholders on the same page.
TickTick - TickTickis a cross-platform to-do list app & task manager helps you to get all things done and make life well organized.
TaskUnifier - TaskUnifier - Task Management Application
The Hit List - Your life is complicated, but managing it doesnt need to be.