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.
Vivox - Vivox is called to be one of the leading chatting platforms for online gamers.
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.
RaidCall - Free & Light. Setting up is fast and easy; with no need to rent or set up servers. Low CPU usage and minimum memory footprint allows for smooth, uninterrupted communication. im. Group Communication.