KG stands alone because he pitches nearly as many perfect games, while combining Tim Duncan's length and frame with a guard's ability to move his feet. Garnett has become a bit more showy about things after getting traded to the Boston Celtics, but his time spent toiling for those awful Minnesota teams prior to that -- and his years spent dominating on some solid-to-great Timberwolves teams prior to that -- were the work of a defensive genius. He just guarded everyone, every play, every feint, every drive, everything. And then he'd get the rebound. Pity that nobody seemed to be paying attention.
Others named include the usual suspects like Bruce Bowen, Ben Wallace, Mt. Mutumbo, etc.
Bonus Link: Celtics Town asks "Is KG Clutch?"