Tox - Send messages, files, create groups and make Tox to Tox audio and video calls. Securely.
M for iOS - Email app with automatic encryption
qTox - A Qt graphical user interface for Tox.
i2pd (I2P Daemon) - i2pd (I2P Daemon) is a full-featured C++ implementation of I2P client
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
I2P - The I2P network provides strong privacy protections for communication over the Internet.