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.
It actually started decades ago with daytime soaps which were designed to still make sense to someone who was busy with housework. Now it just applies to way more shows.