Voltaic Key, Rings of Brighthearth, and Metalworker

Prerequisites

• Voltaic Key on the battlefield
• Rings of Brighthearth on the battlefield
• Metalworker on the battlefield
• 2 or more artifacts in hand
• Metalworker does not have summoning sickness

Steps

1. Activate Metalworker and reveal 2 artifacts to add to your mana pool
2. Activate Voltaic Key to untap Metalworker
3. Rings of Brighthearth triggers allowing you to copy Voltaic Key's ability and untap Voltaic key with the copy
4. Repeat

Results

• Infinite colorless mana
• Infinite untap of all artifacts you control