Sometimes you don't need footage, music, or dialogue from the movie in a teaser or trailer. Sometimes, when your movie is spectacular enough, you can get away with a trailer selling the premise of the film alone. And when the premise of your movie is "a theme park filled with actual living dinosaurs," well, you're in luck.
The first trailer for Steven Spielberg's Jurassic Park functions as a sort of prologue to the film, explaining that scientists found dinosaur blood in mosquitos trapped in amber, and that that blood was used to create living dinosaurs. It builds to this revelation slowly but surely, with the payoff hitting at just the right moment. There's no sizzle reel, Sam Neill, or shots of dinosaurs, because none of it was needed. When you're truly confident in your movie, you know the plot can sell it better than any footage, and Spielberg's team cut one of the best trailers of all time without using a single element from the finished film. As we now know, the end product is just as good as this trailer leads you to believe.