HelpScout - Help Scout is a simple, straightforward way to provide excellent support

Gmail Unsubscriber - Open source alternative to Unroll.me for Gmail

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

Leave Me Alone - Easily unsubscribe from unwanted emails 💌

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

Polymail - Native email app for email productivity.