Turkish-made Turbo chewing gum has a small piece of paper under the wrapper, with an image of a car (or sometimes a bike or a plane) in it. Those were collectibles, and more importantly, it was possible to sell them, or, with skill and luck, gamble on them and increase your collection. The game was like that: two parties would put the collectible cards (more like bits if paper than cards, really) on a flat surface, and then, in turns, would SLAP the cards with their palms to make the cards fly. If one managed to capsize an opponent's card, they would claim the ownership. There are 1620 different cards, says the internet.
I kid you not, I have seen Turbo gum just the other day in a Polish shop in my town. I had no idea those were still a thing.