Certainly NOT Dead Like Me. Still salty about that one.
Serenity and Star Trek as others have said are proabbly my actual favorites. The original Naked Gun movies were based on the short-lived Police Squad show and are as close to maintaining continuity as anything ZAZ could be. Then, the original Transformers animated movie gets more credit than it deserves due to nostalgia and not being a Michael Bay mess, but it had no business being even as good as it was.
This is pretty much what I said to my wife while scritching my dogs. First it'll just be expanded to missing kids and olds, because of course everyone wants to reunite families, but eventually it'll be something that "law enforcement" can request for whatever the hell they want, because after all they're the good guys keeping us safe!