GSC - With GSC, you can pick from any of 14 worldwide datacenters to host your own free voice server.
Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Reddit - Reddit gives you the best of the internet in one place. Get a constantly updating feed of breaking news, fun stories, pics, memes, and videos just for you.
Ripcord - A desktop chat client for Discord and Slack
Twitch Messenger - Desktop and mobile app for Twitch users to communicate with friends and teammates across platforms.
Ziggs - Smoothly Share Content Between Devices!