1 Ulvenwald Bear
IIRC in Yugioh there is only a certain number of Blue-Eyes (from the show?), so you could put a rule on the card 'there may only be X Blue-Eyes on the battlefield at any time', Star Wars CCG used to have permanents that you could have 2 or 3 copies of in play, in addition to stuff you could only have 1 of, the concept would work fine here too, only this could care about both players' boards
Relive the series with iconic scenes, collect cards featuring yo
In the Pokmon Trading Card Game, new sets become legal for tournament play on the second Friday following the sets release
In many cases, it appears as a point/counterpoint exercise aimed at eventually explaining why a card will or will not work
Protecting your cards in sleeves and binders isn't enough: they can continue to be damaged by friction caused by the movement of binder pages, for example