Slack - A messaging app for teams who see through the Earth!
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.
Tealfeed - A knowledge sharing platform to empower creators
Chatib - Chatib is an online chat room where you can meet and chat with new people, make them friends, or even data them online.
All Hands - Async video updates for your team
Chattusa - Chattusa is a social network website that provides a free chat service and lets you connect with people from the USA without any hassle.