Only those of big companies. Some of the best games in these companies are based on indiegames from this source, a tecnologic institut, which offers hundreds of games, the best student works, for free download

https://games.digipen.edu

For example the devs of the Portal series are hired by Valve after present they Student work Narbacular Drop, a 3D puzzle game from 2005 with interconected dimensonal ports like later in Portal.