Abandonware

Abandonware, just like freeware, shareware, etc, is a term for computer games and software that is no longer sold via retail outlets or even supported by its developer. There is also a chance that the copyright of the software/game is in a gray area.

Games normally become abandoned after a certain age, especially if companies go out of business and stop support of the game.

There are currently thousands of "abandoned" games and other software.