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
Houseparty - Brining empathy to online communication.
LiveChat - LiveChat - premium live chat software. Approach customers directly on the website, make connections and drive more sales using LiveChat.
Booyah - Video chat with up to 12 friends at the same time.
Crisp Chat - Multi-channel customer support software
Slack - A messaging app for teams who see through the Earth!