Ms. Marvel, Elastic Ally

The reward condition here is stranger than it looks: it does not care that a creature has high power, it cares that a creature's power is higher than its base. That is a precise buff detector, and it turns the enters-the-battlefield pump into a self-priming engine: give a creature +2/+0, connect, draw a card. The trigger reads any source that lifts power above the printed number, so it fires on temporary combat tricks just as readily as on Equipment, Auras, or +1/+1 counters. Every one-shot buff you cast becomes a cantrip attached to a body, provided that body gets through, and every permanent modifier keeps qualifying turn after turn. The "only once each turn" clamp holds it in check: you cannot flood the board with modified attackers and refill your hand five deep, so it rewards making one attack matter rather than papering counters across the team. Reach adds quiet defensive value on turns spent holding back, letting the 2/2 body ground a flyer while the deck sets up its next swing. What makes the package cohere is the base-power distinction: it is a rules-clean way to reward the act of enhancing a creature without rewarding raw stats, so a mana dork pumped to relevance triggers it while a naturally large creature sitting at its printed power does not. That is a narrower, more deliberate axis than "big creatures draw cards," and it points the deck toward a boost-matters shape rather than a stompy one.