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

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

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.

Kandan - Open Source private chat server. Your own private Chat server in minutes, plus additional features.

Otr.to - A secure peer-to-peer chat in your web browser.

Chattervibe - Chattervibe is a Free Chat Online, Make Friends, and Meet is a social and dating application that is designed for those who want to talk and make new friends online.