LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Clever - syncing between education applications for K-12 schools
Gramlee.com - Online grammar check, proofreading and copy editing services.
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.