qTox - A Qt graphical user interface for Tox.
FluffyChat - Open. Nonprofit. Cute ?
Tox - Send messages, files, create groups and make Tox to Tox audio and video calls. Securely.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Toxic - Toxic is a client with an ncurses interface, written entirely in C.
Molly (Signal fork) - Molly is an independent Signal fork for Android