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.
I hate when biological cloning has some sort of "memory" technomagic scribbled on. Clones don't fucking pick up a dead person's memories, especially not as a default feature!