Beast Whisperer

Green has wanted a creature-based card advantage engine for as long as the color has existed without a clean one, and the closest precedent was always a spell, not a body: Glimpse of Nature did this exactly, once, for a single turn, then went to the graveyard. Putting the trigger on a 2/3 Elf Druid is the design pivot. Now the engine persists, the trigger refreshes every turn cycle, and it folds back into green's own deck the way nothing else there does: the deck is already full of creature spells, so the card asks for no real concession to play it. The trigger fires on cast rather than on an activated ability, so it does not need to survive to the next turn: cast this, then cast another creature the same turn, and the draw is already yours. What keeps it from being a Glimpse-style explosion is the fragility of the body. At 2/3 it dies to almost anything, so the reward is the grind rather than the burst: one card per creature for as long as it lives, on a permanent that opponents are motivated to kill on sight. The kinship with Garruk's Packleader and the later run of "draw when a creature enters" effects is real, but those sit on ETB triggers. This sits on the cast itself, so tokens and copies (which never resolve as cast spells) leave it cold, while recursion and repeated hardcasts feed it in ways ETB engines cannot match.