The new Toy Story movie got me wondering about this. After the first movie, Woody and Buzz dolls were sold that were basically identical in form to the toys in the movie. They probably couldn’t talk, but I can’t be sure because they wouldn’t do it in front of us.
Wonka candy is another example. I don’t know if they’re still sold anywhere, but I can remember Wonka candy bars.
What I’m not talking about are products that exploited a fictional work’s popularity but that weren’t actual things in that universe. So, for example, Star Wars action figures wouldn’t be good examples. I’m talking about items someone in universe could purchase or acquire that became real things after the fictional work became popular.
Anything else come to mind, or did I just exhaust the examples?
A bunch of Harry Potter products became real, including Bertie Bott’s Every Flavor Beans and Chocolate Frogs (though the real chocolate frogs weren’t animated, like the fictional ones were).
EDIT: Oh, and even if Star Wars action figures don’t count, I think there is one toy that does. In an early scene, Luke is seen with a model of a spaceship. I don’t think the “real” version of that spaceship is ever seen; it’s just a toy, on the set. But it of course became a toy in our world, too.
ThinkGeek (sadly no more) put a Tauntaun sleeping bag on their page as an April Fool’s prank one year. It got so much buzz that they actually created one for sale.
As a promotion for The Simpsons Movie, the 7-11 Corporation temporarily rebranded various locations as Kwik-E-Marts, with Duff Beer, Squishees, and Krusty-O’s available for sale.
I think that Spinal Tap (from This Is Spinal Tap) and Otis Day and the Knights (from Animal House) both did some shows and albums, after being invented for those movies.
I think Spinal Tap existed as a… comedy band… before the movie came out. I’m deliberately not researching it.
Otis Day and the Knights came to my college one year, and they cancelled the show due to not enough ticket sales. I was bummed even though I never bought a ticket.
Swingline didn’t make a red stapler prior to Office Space. The prop department painted one red so it would show up better on camera. Later Swingline started offering a red version due to popular demand from fans of the movie.