FusionAuth - FusionAuth is a CIAM platform that is 100% free for unlimited users.
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.
Mountain - Living seamlessly in the menu bar Mountain allows you to manage volumes with ease.
ChatSecure - ChatSecure is a free and open source messaging app that features OTR encryption over XMPP.
Cur - A smart band-aid for pain relief
Keybase Chat - End-to-end encrypted chat built into Keybase