Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
tawk.to - tawk.to is a free live chat app that lets you monitor and chat with visitors on your website or from a free customizable page
Sidequest for Slack - Create and track personal or support team tasks, 100% inside Slack.
LiveChat - LiveChat - premium live chat software. Approach customers directly on the website, make connections and drive more sales using LiveChat.
Roby - Refreshingly simple helpdesk for Slack & Teams users
JivoChat - JivoChat is a live chat that enables you to talk to visitors on your website