GOG.com - DRM-free game store, selling both new and old titles. No clients required.
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
itch.io - An online game marketplace and community.
Wolfram Mathematica - Mathematica has characterized the cutting edge in specialized processing—and gave the chief calculation environment to a large number of pioneers, instructors, understudies, and others around the globe.
Epic Games - Computer game storefront that gives 88% of revenue to developers
Maxima - Maxima is a fairly complete computer algebra system written in Lisp with an emphasis on symbolic computation.