Grammarly - Clear, effective, mistake-free writing everywhere you type.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Hunspell - Hunspell is the spell checker of LibreOffice, OpenOffice.
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
DSpellCheck - Yet Another Notepad++ Spell-checking Plug-In
HelpScout - Help Scout is a simple, straightforward way to provide excellent support