Ajani, Mentor of Heroes

A planeswalker built around a question most of the genre never asks: not "what do I do to the board?" but "what do I do for the creatures already on it?" Both plus abilities point the same direction, which is the design discipline at work here. The counter-distribution mode grows what you have; the card-selection mode digs four deep for the next creature, Aura, or planeswalker to add to the army. There is no minus that interacts with the opponent at all, no removal, no bounce, no defensive tick. Loyalty only ever climbs, and it climbs toward an ultimate that buys time rather than ending the game: a hundred life is a wall, not a wincon, the kind of number that asks an aggressive board to keep doing what it was already doing. That self-contained, all-offense kit is the tradeoff. The counter mode wants a board to act on, so it rewards a deck that is already ahead and accelerates the lead rather than one that needs help climbing out of a hole. The counter mode also folds neatly into anything that cares about +1/+1 counters as a resource, turning a single activation into fuel for outlets elsewhere. It is the rare planeswalker that functions less as a standalone threat and more as a permanent that compounds whatever go-wide or counters-matter plan it lands inside.