Worldwalker Helm

The clever part is a replacement rule that hides inside your other token engines. Every time an effect would mint one or more artifact tokens (Treasures off a sacrifice payoff, Clues off an investigate trigger, Food, Powerstones, or the artifact copies the Helm makes itself), a Map token comes along for the ride. That Map is an explore stapled to an artifact: it grows a creature and smooths the top of your deck at sorcery speed for a modest fee, converting a stream of incidental artifacts into board development and card selection. The second ability closes the loop by copying any artifact token you already control, and because the copy is itself the creation of an artifact token, the replacement effect fires again: copy a Treasure and you get a second Treasure plus a Map, copy a Clue and you get a second Clue plus a Map. The engine feeds itself. What makes it worth building around rather than just running is that neither half asks for a specific token type; it cares only that the token is an artifact, so it slots into anything already making them and quietly upgrades the rate. The brakes are deliberate: the copy ability taps the Helm, and the explore is locked to sorcery speed, so this is a value flywheel rather than a burst payoff. It rewards a board that already produces artifacts on its own clock, then bends that production toward inevitability.