Ichormoon Gauntlet

Every planeswalker you control gains two new loyalty abilities the moment this resolves: a proliferate that costs zero loyalty, and a twelve-loyalty ultimate that hands you the turn. The design trick is that those two abilities feed each other. Proliferate at zero cost ticks every planeswalker (and every other counter you control) upward without the walker ever spending down, so the loyalty math that normally gates an ultimate stops being a ceiling and becomes a countdown you accelerate on your own terms. The second half turns every noncreature spell into a counter-adding trigger: each cast lets you choose a counter on a target permanent and add one more of that kind. Stack those single increments with the free activations and the twelve-loyalty extra turn arrives far sooner than a printed ability that expensive should ever land, and each extra turn is another untap to run the loop again.

What separates this from ordinary counter-support is that it does not care which planeswalker is on the battlefield. As a global artifact it rewrites the ability set of anything with a loyalty line, so a walker whose native ultimate is unremarkable inherits a turn-taking finisher for free, and a cheap early walker becomes an engine rather than a tempo play. Compare the loyalty-multiplier tradition of Doubling Season and The Chain Veil: those amplify what a walker already does, while this bolts on entirely new verbs. It is a value axis first and a combo enabler second, and the ceiling on the second is a full extra turn.