Greater Mossdog

Dredge cards are graded almost entirely on what the keyword recurs, and this one is grading itself on a 3/3 body. That makes it the engine's least glamorous and most honest tool: a creature that mills three to come back, every turn, with no enters-the-battlefield payload to justify the trip. Where a dredger like Golgari Grave-Troll or Stinkweed Imp earns its place by hauling a fat mill number or trading in combat, Greater Mossdog's value is purely structural. It is graveyard volume on a stick, a renewable way to bin three cards a turn while keeping a body you can actually attack or block with. The Dredge mechanic's whole conceit is replacing the draw step with a graveyard-filling loop, and a card with a smaller dredge number and a usable creature fills a different slot in that loop than the big self-mill threats: it is the low-variance pump that keeps the engine ticking when you want fuel without overshooting your library. Nothing about the 3/3 is the point; the point is that returning it costs nothing but three cards off the top, and in a deck built to want those three cards in the bin, that is not a cost at all.