Microsoft Office Access - Access is now much more than a way to create desktop databases. It’s an easy-to-use tool for quickly creating browser-based database applications.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
LiveCode Platform - It is Both Under the GPL and it is also Proprietary if using the GPL version the software you make...
Clever - syncing between education applications for K-12 schools
Redis - Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.
Claroline - Claroline is a collaborative eLearning and eWorking platform.