Wiktionary
trump cards
n. (trump card English)
Usage examples of "trump cards".
Several of the trump cards had been finely shaved on their short edges, so that the stripper-or, now that he knew the secret, Scame himself-could on his deal drop them out of the pack and distribute them whichever way he wanted.
They held the two trump cards -- -Jennings and his son -- in Russia and knew that Mrs.
Quite often he can be inveigled into playing his trump cards early on, instead of holding them until later in the game, when they'll do him more good.