Aboardly - IFTTT for automated customer emailing
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
BurnChurn - 🔥 Reduce churn and track exit feedback for your SaaS
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
Customer.io - We make it easy to send emails triggered by user behavior. Build, measure and improve your emails to activate and retain users
HelpScout - Help Scout is a simple, straightforward way to provide excellent support