Toph, the First Metalbender, Master Transmuter, Retreat to Coralhelm, and Relic of Sauron

Prerequisites

• Toph, the First Metalbender on the battlefield
• Master Transmuter on the battlefield
• Retreat to Coralhelm on the battlefield
• Relic of Sauron on the battlefield

Steps

1. Activate Relic of Sauron by tapping it, adding Activate Master Transmuter by paying , tapping it and returning Relic of Sauron from the battlefield to your hand, putting Relic of Sauron onto the battlefield
2. When Relic of Sauron enters, Retreat to Coralhelm triggers, as Relic of Sauron is a land due to Toph, untapping Master Transmuter
3. Repeat

Results

• Infinite black mana
• Infinite blue mana
• Infinite landfall triggers
• Infinite red mana