Sinuous Benthisaur

The payoff for a land theme that mostly lives at common. A 4/4 for six mana is filler on its own; the enters trigger scales entirely with how many Caves you have accumulated, counting both the ones on the battlefield and the ones sitting in your graveyard. That second half is what elevates the design: it turns the fetch-and-crack lands that fuel a Cave deck into a resource that keeps paying after they've been sacrificed, so the card rewards a strategy that has already been grinding through its own manabase rather than one that just happens to run a few utility lands. The dig is deep but the yield is fixed at two cards, which keeps the ceiling honest: even a huge X only ever refills a hand by two, so this is card selection sharpened by land count, not raw card advantage that snowballs. The rest go to the bottom in random order, a small tax that stops you from stacking your library. This descends from a line of "count your lands of a type" payoffs, but the graveyard clause is what distinguishes it, giving a mid-game body a reason to reach for lands you'd already spent.