LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Clever - syncing between education applications for K-12 schools
Grammarly - Clear, effective, mistake-free writing everywhere you type.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Gramlee.com - Online grammar check, proofreading and copy editing services.
Claroline - Claroline is a collaborative eLearning and eWorking platform.