Watchful Naga

Green has never had a clean way to draw cards off a body it already wanted to run, and this design tucks the refill inside a plain 2/2 that only pays out when you are the one pressing the attack. Exert is the tax: swing and draw, but the Naga then sits through your next untap step, unable to block or attack, no longer minding the flank it was meant to guard. A creature that drew a card on every attack for free would be badly underpriced here; skipping a full turn of the creature's presence is what keeps the rate honest. Because exerting locks it down through the following untap, the engine cannot run on back-to-back combats: you draw, then the Naga spends a turn tapped, then it comes back and you choose again. The decision is never automatic. Attack without exerting and it taps normally, untaps on schedule, and offers you the choice again next combat. Exert it and you buy one card at the price of a turn's board presence. That cadence, on-again then off-again, is the whole appeal: a slow, disciplined trickle of attrition that keeps posing the same trade one swing at a time, gas or a body on the battlefield, but never both in the same breath.