Toph, the First Metalbender, Argothian Elder, and Memnarch

Prerequisites

• Toph, the First Metalbender in hand or on the battlefield or in the command zone
• Argothian Elder on the battlefield
• Memnarch on the battlefield
• available

Steps

1. Give the artifact type to Argothian Elder using Memnarch
2. Activate Argothian Elder by tapping it, untapping it as it's a land due to Toph and another land you control
3. Repeat step 2

Results

• Infinite mana lands you control can produce
• Infinite untap of lands you control
• Infinite untap of nontoken artifacts you control
• Infinite mana nontoken artifacts you control can produce