Yggdrasil - A proof-of-concept scalable IPv6 meshnet, featuring end-to-end encryption, a unique spanning tree...
Gajim - Full featured and easy to use Jabber client
Bitmask - Bitmask is an open source application to provide easy and secure encrypted communication.
CoyIM - CoyIM is a safe and secure chat client.
Windscribe - Windscribe is a desktop application and browser extension that work together to block ads and trackers, restore access to blocked content and help you safeguard your privacy online.
Empathy - Apps/Empathy - GNOME Wiki!