Papershift - Widely used and loved by shift planners & HR Teams of small & medium businesses.

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

TimeTrackApp - TimeTrack Enterprise is ideal for collaboration in teams and companies. At the same time the freelancer version was designed for individuals who want keep track of their projects.

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.

Sawayo.de - The business owner tool which saves hundreds of hours spend on non-value-adding tasks like employee time tracking, compliance research and workflow implementation (available in German).

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.