While there are several different incarnations of Kenton Knepper’s classic Kolossal Killer, one in particular reigns supreme: Heirloom Redux by Mark Elsdon. It requires only 4 cards in your wallet, and its equivoke is entirely consistent: you don’t confusingly alternate between eliminating and keeping cards during the selection process. And with so few cards to carry, you can be ready at all times. Elsdon even provides a logical connection for the off-by-one ploy to the beginning of the effect. It’s just brilliant.
Heirloom Redux is simply a mind blower and a must-have.