GOG.com - DRM-free game store, selling both new and old titles. No clients required.
itch.io - An online game marketplace and community.
Epic Games - Computer game storefront that gives 88% of revenue to developers
GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
Oneplay - Buy and Rent PC &MAC games
Green Man Gaming - A digital distributor for video games.