Caption - Open-source captioning tool to help find the right subtitles.
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Subtly - Learn English with smart subtitles on movies and TV shows
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Bazarr - Bazarr is a companion application to Sonarr and Radarr that manages and downloads subtitles based on your requirements.
Editsaurus - Highlights potential pitfalls in your writing to encourage good habits.