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.

PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.

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

Clever - syncing between education applications for K-12 schools

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

Claroline - Claroline is a collaborative eLearning and eWorking platform.