I'll go first. Mine is the instant knockout drug. Like Dexter's intramuscular injection that causes someone to immediately lose consciousness. Or in the movie Split where there's the aerosol spray in your face that makes you instantly unconscious. Or pretty much any time someone uses chloroform.
Whooshing rocket noise in space, people outrunning explosions, "hero"'s every shot a kill while "baddies" hit nothing.