Grammarly - Clear, effective, mistake-free writing everywhere you type.
Gramara - AI grammar correction with transformers
ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.
Andy Chatbot - Learn and practice English with exercises, grammar and games
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Expresso - The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer with an extensive knowledge of regular expressions.