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.
Qudo – Find Snapchat Friends - Qudo is a great app that helps you Find Snapchat Friends directly from your iPhone.
Otr.to - A secure peer-to-peer chat in your web browser.
ChatIW - Meet and Chat with new friends around the world.
ChatSecure - ChatSecure is a free and open source messaging app that features OTR encryption over XMPP.
Swiping – Make Friends - Swiping is a handy app that lets you Make Friends online.