Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Carrd - Simple, responsive one-page site creator.
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
mmm.page - Dead simple, drag & drop personal websites
JivoChat - JivoChat is a live chat that enables you to talk to visitors on your website
Message.io - Make your chat bots cross-platform