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.
Hunspell - Hunspell is the spell checker of LibreOffice, OpenOffice.
Clever - syncing between education applications for K-12 schools
DSpellCheck - Yet Another Notepad++ Spell-checking Plug-In
Claroline - Claroline is a collaborative eLearning and eWorking platform.