GOG.com - DRM-free game store, selling both new and old titles. No clients required.
Parsec - Streams games locally or over the internet
itch.io - An online game marketplace and community.
Vortex Cloud Gaming - Cloud gaming app allowing to play PC games on Android, PC or even in web browser
GnuPlot - Gnuplot is a portable command-line driven interactive data and function plotting utility.
Shadow - Transform any device into a supercharged gaming machine.