Szarel, Genesis Shepherd, Puppeteer Clique, and Yahenni, Undying Partisan

Prerequisites

• Szarel, Genesis Shepherd on the battlefield
• Puppeteer Clique on the battlefield
• Yahenni, Undying Partisan on the battlefield

Steps

1. Activate Yahenni by sacrificing Puppeteer Clique
2. When Puppeteer Clique dies, its persist ability and Szarel trigger
3. Resolve the persist trigger, returning Puppeteer Clique from your graveyard to the battlefield with a -1/-1 counter on it
4. When Puppeteer Clique enters, it triggers, putting a creature card from an opponent's graveyard onto the battlefield under your control
5. Resolve the Szarel trigger, putting a number of +1/+1 counters on another creature you control
6. Resolve the Yahenni ability from step 1
7. Activate Yahenni by sacrificing the creature returned in step 4
8. When the creature dies, Szarel triggers, putting a number of +1/+1 counters on Puppeteer Clique
9. Resolve the Yahenni ability
10. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters