Emmara, Soul of the Accord, Agatha's Soul Cauldron, and Aphetto Alchemist

Prerequisites

• Emmara, Soul of the Accord on the battlefield
• Agatha's Soul Cauldron on the battlefield
• Aphetto Alchemist in exile

Steps

1. Activate Emmara using Aphetto Alchemist's ability by tapping it
2. Emmara triggers, creating a 1/1 Soldier creature token
3. Resolve the Emmara ability from step 1, untapping it
4. Repeat

Results

• Infinite ETB
• Infinite creature tokens