Tendershoot Dryad

The token trickle runs on every upkeep, not just yours, and that detail is the whole engine's logic: the dryad manufactures a Saproling at the start of every player's turn, so the board inflates whether you are taking the turn or waiting for your next one. The 2/2 body threatens nothing, which is precisely why it gets to do so much work: it never needs to attack, only to survive and keep spitting out fodder. Ascend closes the loop the first ability opens. The tokens it generates are permanents, and permanents are exactly what the city's blessing counts, so the card ratchets itself toward its own ten-permanent threshold. Cross it and every Saproling gets the +2/+2, turning a pile of 1/1 chip damage into a swarm of 3/3s that arrives without a second card ever leaving your hand. The buff is a static ability on the dryad itself, though, so removal aimed at it does more than choke off future supply: the blessing sticks with you permanently once earned, but the +2/+2 evaporates the instant the dryad dies, and the swarm snaps back to a field of 1/1s. That fragility is the counterweight to a card that otherwise sets its own win condition, scales the payoff off the same permanents it makes, and asks for almost nothing in deckbuilding beyond the green to cast it.