Mumble - Mumble is an open source, low-latency, high quality voice chat software primarily intended for use...
Discord - Step up your game with a modern voice & text chat app. Crystal clear voice, multiple server and channel support, mobile apps, and more.
Mohawk Voice - Mohawk Voice is a low resource, high quality VoIP program which is free to download and use.
GSC - With GSC, you can pick from any of 14 worldwide datacenters to host your own free voice server.
Steam Chat - Steam Chat is a chatting app for Steam users that enables them to chat through their cell phones and get updated with what is happening.
Vivox - Vivox is called to be one of the leading chatting platforms for online gamers.