Seedship Agrarian

Most landfall creatures are passive collaborators: you play lands on your own schedule, and the counters pile up as a side effect of doing what you were doing anyway. This one manufactures its own fuel. Every tap hands you a Lander, and cracking that Lander drops a basic onto the battlefield, which pings the landfall trigger for a counter. Swing with it, sacrifice the token, and it comes back untapped next turn a little bigger, having paid for its own growth. The engine feeds itself, which is unusual for a green four-drop that would otherwise be a 3/3 body with a growth clause bolted on.

Crucially, the tap trigger is not restricted to attacking, and that is where the design widens. Any way to tap it (a convoke cost, a tap-to-activate ability, an effect that taps your own creatures) spins the token generator without ever putting the body in front of blockers. The Landers pull double duty as fixing and as ramp, so the counters ride along on top of work the tokens were doing regardless. The mana is what keeps it honest: each Lander costs two and a sacrifice to cash in, so the counters accrue only as fast as you can afford to convert the artifacts. This is a green midrange piece for a deck with reasons to tap its own creatures beyond combat, where the growth is incidental to a mana engine that was already earning its keep.