Solid - Solid is a solution for online business meetings.
Flow - Stop managing projects from your inbox.
Conode - A simple editor to organize meetings
Rocket.Chat - Rocket.Chat is a Web Chat Server, developed in JavaScript, using the Meteor fullstack framework.
Meetingbird - Powerful meeting scheduling and notes — right in your calendar
Zulip - Chat for distributed teams. Zulip combines the immediacy of real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones.