The Roselli Brothers blow many casino scammers completely out of the water. Over a five year period between 1995 and 2000 they obtained $37 million + from casinos in Nevada, New Jersey,and Puerto Rico. They did all of this without risking a penny of their own, or without any game specific con.
In fact they achieved their con via what amounts to identity theft. The bothers hired a hacker to find individuals with good credit scores, then they opened new accounts under those individuals names, depositing $50,000 in the process. This deposit then made it easy for them (using their fake ID) to gain a line of credit with casinos, sometimes over time to the point of upward of a million dollars.
This went on for 5 years and the brothers even had a big blowout night in Las Vegas where they gambled up to $100,000 per hand. The brothers then cashed out their winnings and disappeared. It was 6 months before the FBI releaised that the scam had even taken place, at which time the pair were long gone. Funnily though it was discovered that even The Roselli Brothers were stolen identities (of brothers who died years prior) and so they still to this day have no idea who the pair were.