Not exactly a “scene,” but something to induce you to sit through the credits: Early James Bond films always ended with (after the credits) something to the effect of: “James Bond Will Return in […]” with the name of the next movie. I don’t know if that practice goes all the way back to Dr. No. (1962), but it was in use for most of the Connery and Moore films.
Films used to give the cast upfront, in various formats, but obviously in imitation of theater programs. DW Griffith sometimes did “credits” by going to a close-up in a framed oval of each principal, and giving the name of the character, followed by “played by Miss Lillian Gish,” or whomever, and then resuming the film after a few seconds, when the character was seen the first time. Lesser characters, but ones who still needed a credit, would have it below their names in the intertitle.
Most early films were less fancy, and just displayed a card that looked like a page from a program.
The film* Frankenstein*, 1931, had “The Monster … ?” as the last credit in the opening titles. At the end of the film, the credits were repeated under “A Good Cast is Worth Repeating,” and this time it said “The Monster … Karloff”; as far as I know, this was the first time the credits were displayed at the end of a film. The sequel *The Bride of Frankenstein *also did the “A Good Cast is Worth Repeating,” bit in 1935, and this seemed to start the credits at the end trend.
Not exactly what was being asked, but the “secret” of who played the monster was an Easter egg of sorts-- except AFAIK, William Pratt wasn’t billed as “Karloff” until the film Frankenstein, and was mostly uncredited in the many films he had previously appeared in. He was “that guy.” The first name, Boris, came from a character he played in a comedy just prior to Frankenstein. The comedy, Cracked Nuts, starred all sorts of people who were huge box office draws in 1931, and are almost unknown now. Anyway, billing him as “Karloff” was almost the same as billing him as a “?” in 1931. If they’d billed him as “Boris from Cracked Nuts,” people would have known who he was.
Weird, the first one I remember seeing and realizing that is what it was is a movie from 1996 called Head Above Water (starring Cameron Diaz). I have seen some of the others on that list above before that movie, but I guess that was when I first realized.
The Curse of the Were-Rabbit might be an almost-example.
The closing credits were played with a back-drop of cartoon rabbits floating around the screen. At the end of the credits, there appeared a message in somewhat larger type, declaring:
When this statement appears on the screen, one of the rabbits floating around the screen promptly conks his head against one of the letters of the message, and falls down off the bottom of the screen.
I heard in the movie Big, the studio tacked on an alternate ending where a young Susan comes into Josh’s classroom, but since it was after the credits rolled, most of the audience had already left the theater and never saw it.