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.

ClearChat - If you're hosting a public video chat then it can attract unwanted attention from troublemakers.

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

Convoy - Local and regional trucking on demand

Flow - Stop managing projects from your inbox.

Duuoo - Meetings that Matter