Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
Live Chat by Landbot - Live chat that combines chatbots with human chat
Avochat - Support your customers with live chat + SMS for business
Video Live Chat for Websites - Provide real-time video chat support with screen sharing
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.