Mumble - Mumble is an open source, low-latency, high quality voice chat software primarily intended for use...
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
Discord - Step up your game with a modern voice & text chat app. Crystal clear voice, multiple server and channel support, mobile apps, and more.
Playnite - Source code generated using layoutit.com
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.
Batocera.linux - Batocera.linux is an open-source and completely free retro-gaming distribution that can be copied to a USB stick or an SD card with the aim of turning any computer/nano computer into a gaming console during a game or permanently.