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 am so very sick and tired of born-special chosen ones of epic destiny, and by extension, I am also so very tired of secret societies that actually run everything from behind the scenes that have their secret wishes carried out by what amount to magic cops that were born special with an epic destiny. When these things are perceived as an acceptable status quo or even as good in the fiction, that's especially exhausting.