Grammarly - Clear, effective, mistake-free writing everywhere you type.

Write App - No-distraction writing tool for your productivity.

LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.

Hemingway - Hemingway App makes your writing bold and clear.

Hunspell - Hunspell is the spell checker of LibreOffice, OpenOffice.

ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.