There is one more way for a green card cases. It is annual green card lottery from United States Government. The electronic system choose huge amounts of people around the world to be granted with a green card by choosing the winning numbers. Real lottery but the prize is a green card and permanent residency in the United States of America.
Every year the US Government make a lottery which is Diversity Lottery for a Green Card. United States Department of State, Bureau of Consular Affairs offers the Electronic Diversity Visa Lottery. This is Applicant Entry System which is one and the only electronic system for applying a green card as a lottery game.