Hemingway - Hemingway App makes your writing bold and clear.
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Blurt - Compose efficiently. Edit smartly. Stay on track. Blurt is all you need to write — in one sleek tool.
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Write App - No-distraction writing tool for your productivity.
Editsaurus - Highlights potential pitfalls in your writing to encourage good habits.