Gravpack Monoist

The trade is baked into the death trigger: a fragile 2/1 flier that leaves a durable 2/2 ground blocker behind, so the card is worth two bodies whenever it dies. That asymmetry, evasive attacker up front and a replacement body after, is what makes it a natural fit for sacrifice-fueled shells. A one-toughness flier is easy to feed to any outlet, and the Robot it produces is fresh fodder for the next one, so each copy is effectively two triggers' worth of enter-and-leave value for the price of a single card. What keeps this honest is the token's tapped clause: the Robot arrives unable to block the turn its parent dies, defending next combat rather than this one. That single word of timing separates the card from a clean removal-eater that instantly rebuilds your board; you rebuild a turn late, and against a fast clock that turn matters. On offense it chips in the air; on defense the token lingers; in a deck that cares about creatures dying, it quietly makes every removal spell your opponent points at it a slightly worse trade than they wanted. Plain black value, but value that keeps giving after the flier is gone.