Patron of the Moon, Selesnya Sanctuary, and Horizon Explorer

Prerequisites

• Patron of the Moon on the battlefield
• Selesnya Sanctuary in hand
• Horizon Explorer on the battlefield
• available

Steps

1. Pay to activate Patron of the Moon, putting Selesnya Sanctuary from your hand onto the battlefield untapped due to Horizon Explorer
2. When Selesnya Sanctuary enters, it triggers
3. Activate Selesnya Sanctuary by tapping it, adding two mana
4. Resolve Selesnya Sanctuary's triggered ability, returning it from the battlefield to your hand
5. Repeat

Results

• Infinite green mana
• Infinite landfall triggers
• Infinite white mana