Fists of Flame

The pump spell that pays for itself twice over: the cantrip is not just card advantage, it is the payload. Because the buff scales with cards drawn this turn (including the card the spell itself draws), casting it is never worse than +1/+0 with trample, and if you have already spun through a chunk of your library it becomes a lethal number attached to a single attacker. That doubling is the whole design tension. A cheap cantrip trick is normally a fair rate; this one hooks its size directly to a resource the pilot is already spending on other spells, so a hand full of Manamorphose, cheap draw, and prowess enablers turns the buff from a nudge into a kill. Trample is the delivery mechanism, making sure the accumulated power lands on a face rather than getting chumped away. It reads as a modest combat trick and functions as a spell-count finisher stapled to a card that replaces itself: the more draws you have stacked, the more this does. The instant speed matters too, letting the pump wait until blocks are declared before revealing how far the turn's card count has actually climbed.