ZenDesk - Zendesk is a beautiful, lightweight help-desk solution.
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.