Nissa, Worldwaker

The untap clause is the part that bent green planeswalkers out of shape. Most planeswalkers tax your mana: you cast them, then you have used your turn. This one gives mana back. Untapping four Forests on the +1 means she effectively pays for herself the turn after she lands, and in a deck flush with Forests she funds an extra spell every turn she ticks up while protecting herself from racing to a slow ultimate. The other +1, animating a land into a 4/4 trampler that is still a land, turns spare mana into a clock, and the ultimate is less a finisher than a guarantee: every basic in the deck, onto the battlefield, all of them 4/4 tramplers. The tension she resolves is the one green never quite solved before: how to make a ramp payoff that ramps and threatens in the same card without asking you to dedicate a turn to drawing cards or finding fatties. The cost is that all of it keys off Forests specifically, not green permanents, not generic lands, so she rewards the basic-heavy mana base and goes quiet in a deck splashing across many colors. That narrow requirement is exactly what made her a four-of in the green decks built to feed it.