As one of the most prominent and powerful duelists in all of Yu-Gi-Oh! history, Kaiba’s mark on the anime series is unparalleled. Save for Yugi, he is one of the duelists we most often watch in battles. With that in mind, it makes sense that Kaiba has used a lot of different decks in his time.
With so many decks, it also makes sense that fans might have forgotten quite a few cards that Kaiba has used in the past for various different reasons.
While Kaiba most-often used Saggi the Dark Clown to activate Crush Card, in the Pyramid of Light movie, he some reason used Peten the Dark Clown, and that was the only time that he was ever the card. It was a much more violent version of Saggi that actually wielded a knife and literally stabbed Yugi, so that’s a nice little memory that anyone who has seen the movie probably remembers fondly.
Kaiba only dueled once in the Grand Championship arc, against Zigfried. As such, fans might have forgotten some of the cards that he used in the duel. This includes Flat Lv 4, a trap card. Flat Lv 4 can be used when either player’s monster is destroyed. Both duelists can then summon a level four monster to their side of the field, which is a very powerful effect no matter the situation.
Blue-Eyes Shining Dragon is a variant of the Blue-Eyes White Dragon that Kaiba only used once, also in the Pyramid of Light movie. The card was won by Kaiba from Pegasus as the card that would be able to defeat the God Cards.
However, the Pyramid of Light card was also slipped into Pegasus’s deck in order to trick Kaiba into playing it. It’s a shame that viewers never got to see Kaiba use this card again, as it was very interesting and underutilized.