GOG Galaxy - Truly gamer friendly, DRM-free online gaming platform.
GOG.com - DRM-free game store, selling both new and old titles. No clients required.
Epic Games - Computer game storefront that gives 88% of revenue to developers
Origin - Origin is your new digital playground. It’s where you go to find the best that EA has to offer.
itch.io - An online game marketplace and community.
Lutris - Lutris is an open source gaming platform for GNU/Linux.