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

irssi - Irssi is a terminal based IRC client for UNIX systems.

Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

WeeChat - WeeChat is a fast, light and extensible chat client.

LiveChat - LiveChat - premium live chat software. Approach customers directly on the website, make connections and drive more sales using LiveChat.

KVIrc - KVIrc is a free portable IRC client based on the excellent Qt GUI toolkit.