Migratory Greathorn

Green's ramp lineage runs through creatures that fetch a land as they hit the table: the Sakura-Tribe Elder tradition, the various titans, bodies that pay for themselves by advancing the mana. This grafts that trigger onto mutate, which is the genuinely novel wrinkle. Cast it face-up for and it's a plain 3/4 with no fetch at all: the land arrives only on a mutate. Pay to stack it over or under one of your own non-Human hosts, and the merge searches out a single basic onto the battlefield tapped. The ownership requirement rides alongside the Human exclusion, and together they narrow the host pool more than the rate suggests: no borrowed or stolen threats to pile onto, and none of the many Human commanders eligible to receive the stack. The acceleration is real (a land straight to the battlefield is more mana) but deliberately modest: one basic, entering tapped, so no explosive turns and no fetching duals. What keeps the card in motion is that the trigger fires on every mutate, not just the first. Each additional mutate creature you pile onto the same host is another basic, so the ramp scales with your commitment to the stack beneath it rather than arriving all at once. A durable midrange body up front, a land per merge, and a growing bundle of stacked abilities riding on one set of stats.