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.

Chatterino - Chatterino is a chat client for twitch chat.

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

Chatty - Chat with strangers all around the world in Messenger

Flow - Stop managing projects from your inbox.

Restream Chat - Restream Chat is a versatile software that permits you to streamline multiple chats in one place.