FluffyChat - Open. Nonprofit. Cute ?
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Molly (Signal fork) - Molly is an independent Signal fork for Android
Mi Airit - Mi Airit a chat app that helps you communicate messages to the right people without receiving unwanted responses or reactions.
aTalk - An encrypted instant messaging with video call and GPS features for android.
NYNJA - NYNJA is an all-in-one communications tool that comes with real-time support to share files and chat.