I have a bunch of old cards that aren't even made anymore. My deck is actually intrestingly enoguh, diverse in many differnet types of cards. I have swamps, islands, mountains, and forests, as well as monsters, spells, and counterspells for each. I play the deck agaist two friends who have a few hundred cards in games that end up lasting for at least two hours. My instant death cards are numerous, making the REALLY strong, even upgraded cards useless, especially Banishing Death, which kills a monster permanately, without you being able to bring them back, regardless of the cards you have. I have three monstrous growth cards, making even my weakest cards pretty good, even if only for one round.
I Have a REALLY rare card called King's Assassin, a 1/1 Black card where, when it comes into play, it instantly kills any one tapped creature instantly. He's fun to use when someone pumps up a juggernaut on the field and uses it. I've yet to lose one on one, so i think i'm at least pretty good.