Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Grammarian PRO3 - Grammarian PRO3 is a feature-rich grammar checker that enables you to write better content without taking assistance from the English teacher.
Lingvist - Lingvist helps you take your foreign language skills to the next level with a broad selection of exercises and lessons.
Gramlee.com - Online grammar check, proofreading and copy editing services.
Language Learning with Netflix - Use movies as study material for language learning
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.