Playnite - Source code generated using layoutit.com
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
Photon Game Manager - Photon is an advanced game launcher that is designed to make your game collection look amazing.
QuickPlay - Quickplay the universal emulator Frontend
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.
GOG Galaxy - Truly gamer friendly, DRM-free online gaming platform.