Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Talkus - Chat with your website users from Slack
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
Nertivia - Chat Client - Chat with friends or anyone around the world, free gif and emoji support.
GoSquared Live Chat - Beautiful, simple, and free live chat for your website
Speaklyn - Website visitors chat with you on Facebook Messenger