Metalworker, Retreat to Coralhelm, Seat of the Synod, and Urza, Prince of Kroog

Prerequisites

• Metalworker on the battlefield
• Retreat to Coralhelm on the battlefield
• Seat of the Synod on the battlefield
• Urza, Prince of Kroog on the battlefield
• You have at least three artifact cards in hand
• Metalworker does not have summoning sickness

Steps

1. Activate Metalworker by tapping it and revealing at least three artifact cards from your hand, adding at least six
2. Activate Urza by paying , creating a token copy of Seat of the Synod that is a 1/1 Soldier
3. When the Seat of the Synod token enters the battlefield, Retreat to Coralhelm triggers, untapping Metalworker
4. Repeat
5. If you have four or more artifact cards in hand, this combo nets infinite colorless mana, and you may target any artifact you control to get infinite copies of them

Results

• Infinite colorless mana
• Infinite copies of each artifact you control
• Infinite creature tokens
• Infinite ETB
• Infinite landfall triggers