GOG.com - DRM-free game store, selling both new and old titles. No clients required.
LaunchBox - LaunchBox is a portable, box-art-based games database and launcher for DOSBox, emulators, arcade cabinets, and PC Games. Download it free!
itch.io - An online game marketplace and community.
Playnite - Source code generated using layoutit.com
Epic Games - Computer game storefront that gives 88% of revenue to developers
GameRoom - Make your video-games library shine!