Robaran Mercenaries, and Ioreth of the Healing House

Prerequisites

• Robaran Mercenaries on the battlefield
• Ioreth of the Healing House on the battlefield

Steps

1. Activate Robaran Mercenaries using Ioreth's second ability by tapping it, untapping Ioreth and another legendary creature
2. Activate Ioreth's first ability by tapping it, untapping Robaran Mercenaries
3. Repeat

Results

• Infinite untap of legendary creatures you control
• Infinite mana legendary creatures you control can produce