100 standard size Deck Protector sleeves in each pack
Outside of a few very specific cards (which will be mentioned first) that require deck sizes above the minimum, all the other reasons you might want to are more fitting to casual magic: Battle of Wits - A win condition that specifically requires you to have more than 3 times the minimum deck size left in your deck to win means starting with about 4 times that minimum, if not more
Ill start by looking at our mana curve: 70 total cards plus 39 lands equals nine cards too many, so we need to make some cuts
This can be easily achieved by just paying more for Ballista, having an anthem or lord effect in play, or swinging with another lifelinker to generate an extra counter on Ballista before going off in your second main phase
While supplies last, you can receive the traditional foil Buy-a-Box promotional card: Omnath, Locus of All
Unlike in chess, however, you can beat your MTG opponent in one turn with just the right combination of cards