Yoast - Yoast offers plugins to improve SEO and optimize web sites and blogs.
Clever - syncing between education applications for K-12 schools
Jackmail - A newsletter plugin for Wordpress.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Wordfence - Comprehensive security plugin for WordPress.
Claroline - Claroline is a collaborative eLearning and eWorking platform.