itch.io - An online game marketplace and community.
The Indie Gala - Buy a bundle of games, you decide the price, and support charity in the process.
Ubisoft Club - Ubisoft Club app enables you to get updates about your favorite games timely.
Humble Bundle - Buy a bundle of games, you decide the price, and support charity in the process.
GOG.com - DRM-free game store, selling both new and old titles. No clients required.
Fanatical - Buy awesome games. Pay a fraction of the retail price!