Koll, the Forgemaster, Hero's Blade, Zabaz, the Glimmerwasp, and Krark-Clan Ironworks

Prerequisites

• Koll, the Forgemaster on the battlefield
• Hero's Blade on the battlefield
• Zabaz, the Glimmerwasp on the battlefield
• Krark-Clan Ironworks on the battlefield
• Hero's Blade attached to Zabaz

Steps

1. Activate Krark-Clan Ironworks by sacrificing Zabaz, adding
2. Zabaz dies, triggering its modular ability and Koll
3. Resolve the Zabaz trigger, putting a +1/+1 counter on any artifact creature you control
4. Resolve the Koll trigger, returning Zabaz from your graveyard to your hand
5. Cast Zabaz by paying
6. Zabaz enters the battlefield, triggering Hero's Blade, attaching Hero's Blade to Zabaz
7. Repeat

Results

• Infinite +1/+1 counters on artifact creatures you control
• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count