Chatib - Chatib is an online chat room where you can meet and chat with new people, make them friends, or even data them online.

Frysbe - Frysbe: Make global friends at random and the fling app comes up with features to send messages to strangers from every corner of the world to expand your social circle.

ChatSecure - ChatSecure is a free and open source messaging app that features OTR encryption over XMPP.

PenPal World - Connect with people all over the world

Element.io - Secure messaging app with strong end-to-end encryption, advanced group chat privacy settings, secure video calls for teams, encrypted communication using Matrix open network. Riot.im is now Element.

Unbordered - Unbordered app comes up with features to help you in finding the perfect language practice and exchange partners so you can practice foreign languages right through your mobile phone.