Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Gainsight - Customer Success for the New Enterprise
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
Hubspot Service Hub - HubSpot's customer service software makes supporting customers easy. Help your customers on the channels they prefer, while driving efficiency for your team.
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
Churnzero - ChurnZero is the Customer Success Platform built for growing SaaS and subscription businesses.