Veilborn Ghoul

Recursion priced into the land drop: every Swamp you play after this hits the bin buys it back, so the card asks nothing but a mono-black manabase to keep refilling your hand. That trade is paid for twice over. The body is a 4/1 that can't block, an attacker only, glass on defense and fragile to anything that pings; and the return is a may-trigger keyed to a single mundane event, not a free recursion engine. What it builds is a steady stream of expendable bodies for decks that want them: graveyard fodder for delve and exploit, food for sacrifice outlets, a reusable beater you don't mind throwing under a removal spell because it comes home next turn. The Swamp clause is the discipline here, tying the loop to a resource you spend anyway rather than a mana cost you'd pay to abuse it, which keeps a four-power recursive attacker from running away. This sits with the other self-returning black creatures that treat the graveyard as a holding pen, and it pulls that off without an activation, an exile clause, or a life payment: just the natural rhythm of dropping lands across a long game.