Tezzeret the Seeker

The minus-X ability is the reason this planeswalker exists, and it is a genuinely unusual piece of design: a loyalty-driven artifact tutor that puts the card directly onto the battlefield rather than into hand, scaling exactly to the loyalty you are willing to spend. Land him on an empty board and the cheap tutors are immediate (a zero-cost mana rock, a one-mana stax piece), but every point you sink into the minus is a point off the body, so the ability negotiates against itself: the bigger the target, the more exposed he is the moment he resolves it. The plus-one is built to refund that tension, untapping two artifacts to bank mana or re-arm an activated rock, which is why he reads less like a threat and more like an engine that wants a battlefield already humming with artifacts before he arrives. That dependency is the whole personality: he is close to dead with no artifacts in play, and overwhelming the turn the artifacts outnumber the answers. The ultimate, animating your entire artifact suite into 5/5 attackers, is the kicker that turns a mana base into a lethal board, a payoff that only the deck he was designed to anchor can actually reach. He sits at the head of a specific lineage of Tezzeret cards that all tutor, untap, and weaponize artifacts in slightly different proportions; this is the version where the search clause does the heavy lifting.