Fain, the Broker + Intruder Alarm + Pitiless Plunderer + Yahenni, Undying Partisan

Fain, the Broker

Intruder Alarm

Pitiless Plunderer

Yahenni, Undying Partisan

How it works

1. Activate Fain's third ability by tapping it and sacrificing another artifact, creating a 2/1 Inkling creature token.
2. When the Inkling enters the battlefield, Intruder Alarm triggers, untapping all creatures.
3. Activate Yahenni by sacrificing the Inkling.
4. When the Inkling dies, Pitiless Plunderer triggers, creating a Treasure token.
5. Resolve the Yahenni ability.
6. Repeat.

This loop relies on Fain, the Broker's ability to sacrifice an artifact—like a Treasure token—to churn out a 2/1 Inkling creature token, which immediately triggers Intruder Alarm to untap your entire board. That fresh entry lets you sacrifice the Inkling to Yahenni, Undying Partisan, which in turn triggers Pitiless Plunderer to replace the sacrificed artifact by dropping a brand-new Treasure token. Because Intruder Alarm keeps every creature untapped and Pitiless Plunderer funds Fain's loop with each death, you can infinitely repeat the process to generate endless sacrifices, death triggers, and mana.