Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Speaklyn - Website visitors chat with you on Facebook Messenger
GoSquared Live Chat - Beautiful, simple, and free live chat for your website
Firehose Chat - firehosechat.com
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
Chatra - Live chat software that helps to increase revenue and collect feedback providing an easy way for website owners to talk to visitors in real time.