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.

Discord - Step up your game with a modern voice & text chat app. Crystal clear voice, multiple server and channel support, mobile apps, and more.

Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.

Mumble - Mumble is an open source, low-latency, high quality voice chat software primarily intended for use...

Twitch Messenger - Desktop and mobile app for Twitch users to communicate with friends and teammates across platforms.

Twitch - Twitch is one of the most prominent streaming services around, serving as a platform primarily for video game and pop culture streamers.