Grammarly - Clear, effective, mistake-free writing everywhere you type.
Spell - Deep Learning and AI accessible to everyone
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Hunspell - Hunspell is the spell checker of LibreOffice, OpenOffice.
Spell It Out - Spelling out tech acronyms so you can be in the know.
ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.