Fain, the Broker + Chatterfang, Squirrel General + Intruder Alarm + Cathars' Crusade
Fain, the Broker
Chatterfang, Squirrel General
Intruder Alarm
Cathars' Crusade
Infinite artifact ETBInfinite artifact LTBInfinite artifact sacrifice triggersInfinite artifact tokensInfinite colored manaInfinite creature tokensInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite Treasure tokensInfinite untap of creaturesReduce the toughness of creatures opponents control to 0Infinite +1/+1 counters on creatures you control
How it works
Activate Fain's second ability by tapping it and removing a counter from a creature you control, creating a Treasure artifact token and a 1/1 Squirrel creature token.
When the Squirrel enters the battlefield, Intruder Alarm and Cathars' Crusade trigger.
Resolve the Intruder Alarm trigger, untapping all creatures.
Resolve the Cathars' Crusade trigger, putting a +1/+1 counter on each creature you control.
Repeat.
Once you have infinite Treasure and Squirrel tokens, you may activate Fain's other abilities.
This clever loop starts with Fain, the Broker tapping to harvest a counter from a creature, spinning out a Treasure token and triggering Chatterfang, Squirrel General's replacement effect to flood the board with an extra Squirrel alongside it. Every time that Squirrel enters the battlefield, Intruder Alarm springs awake to untap Fain while Cathars' Crusade pumps every creature you control with fresh +1/+1 counters. Because Fain's counter-removal action leaves you with plenty of newly minted counters to spare, you can continuously tap, untap, and repeat the cycle to generate infinite treasures, squirrels, and ever-growing stats.