STATEN ISLAND, N.Y. — On a recent Saturday morning, the venue doors opened and the room quickly filled, with kids clutching binders, longtime collectors scanning tables and vendors setting up displays ranging from single cases to sprawling showcases.
At the center of it all was Matty Steven, 44, of Dongan Hills, moving easily through the room, greeting guests, checking layouts and making sure everything was running on time.
Steven, a retired NYPD officer, is the founder of Matty Steven Sports Cards Promotions LLC and the driving force behind a fast-growing series of card shows on Staten Island…