LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Scribbr - Scribbr is an online proofreading and editing service used for the academic activities of the students.
Grammarly - Clear, effective, mistake-free writing everywhere you type.
EditMyPaper.ca - Fast and accurate English editing for essays, general papers, research papers and manuscripts.
Gramlee.com - Online grammar check, proofreading and copy editing services.
GradeProof - Proofreading with Artificial Intelligence