Facebook Messenger Kids - Safer and More Fun Video Calls and Messaging
Empathy - Apps/Empathy - GNOME Wiki!
Stack App - Stack is a Tweetdeck for your social apps
Psi-IM - Psi-IM is a messaging program that is designed for the XMPP network.
Caprine - Elegant Facebook Messenger desktop app
Gajim - Full featured and easy to use Jabber client