New York 1901: Goons of New York is a promotional expansion pack for New York 1901 that adds five new "Boss" cards that give special powers to the players who control each district on the game board.
Once all players in the game have reached the Silver Age, you look to see who controls the most territory of each color on the game board (with pink being excluded in two-player games).
Whoever controls the most of a color takes control of that boss, and at the start of each of your subsequent turns, you can use the "goon power" of one of your bosses to place a goon in a particular location, such as on a street or on a specific Bronze Age skyscraper. You'll score points for this goon based on certain conditions, but if someone ever controls more territory of this color than you, that player takes control of the boss and you have to say goodbye to those goons.
For more information, visit the BGG listing.