Slack - A messaging app for teams who see through the Earth!

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

HeySpace - HeySpace is the only free task and simple project management software with communication and collaboration feature.

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.

Infolio - All-in-one project collaboration suite for fast results and easy teamwork

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