LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
FlashAcademy - The language school in your pocket! 🎓
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Pronounce Names - How to correctly pronounce people's names
Editsaurus - Highlights potential pitfalls in your writing to encourage good habits.
BRAINYOO - Easy cross-platform learning with flashcards.