Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Demonsaw - Demonsaw is the next leap in the evolution of a free Internet, and the debut of social cryptography.
MyChat - Secure instant messenger for any network
Jitsi - Open-source video calling and chat platform.
Ubiq Security - Enable developers to build encryption into apps in minutes
Gajim - Full featured and easy to use Jabber client