Juniper Order Ranger, and Yahenni, Undying Partisan

Prerequisites

• Juniper Order Ranger on the battlefield
• Yahenni, Undying Partisan on the battlefield

Steps

1. Activate Yahenni by sacrificing the persist creature
2. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When the persist creature enters, Juniper Order Ranger triggers, putting a +1/+1 counter on the persist creature and Juniper Order Ranger
4. Resolve the Yahenni ability
5. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers