Along with Pokémon, Digimon, and Dragon Ball, Yu-Gi-Oh! was a gateway to the world of anime for a lot of us. Of course, watching it as kids, a good number of us didn't even know that what we were watching was, in fact, anime. Most people who enjoyed the anime also developed an interest in the card game all those kids were playing, called Duel Monsters. Luckily, collecting Yu-Gi-Oh! cards was possible in the real world as well. Although no monsters popped up when you played, collecting cards, building decks, and dueling with friends was still tons of fun.