Barret, Avalanche Leader, Sword of the Meek, Krark-Clan Ironworks, and Chatterfang, Squirrel General

Prerequisites

• Barret, Avalanche Leader on the battlefield
• Sword of the Meek in hand
• Krark-Clan Ironworks on the battlefield
• Chatterfang, Squirrel General on the battlefield
• available

Steps

1. Cast Sword of the Meek by paying
2. When Sword of the Meek enters, Barret's first ability triggers
3. Holding priority, activate Krark-Clan Ironworks by sacrificing Sword of the Meek
4. Resolve the Barret trigger, creating a 2/2 Rebel creature token and a 1/1 Squirrel creature token due to Chatterfang
5. When the Squirrel enters, Sword of the Meek triggers, returning itself from your graveyard to the battlefield attached to the Squirrel
6. Repeat from step 2

Results

• Infinite ETB
• Infinite colorless mana
• Infinite creature tokens