Ephemerate, Felidar Guardian, and Preston, the Vanisher

Prerequisites

• Ephemerate in hand
• Felidar Guardian on the battlefield
• Preston, the Vanisher on the battlefield
• available

Steps

1. Cast Ephemerate by paying , blinking Felidar Guardian
2. Felidar Guardian and Preston trigger
3. Resolve Felidar Guardian's trigger, blinking a land you control
4. Activate that land by tapping it to add one mana
5. Resolve Preston's trigger, creating a 0/1 Illusion token copy of Felidar Guardian
6. The token enters the battlefield, blinking the nontoken Felidar Guardian
7. Repeat from step 2
8. Once you have infinite mana and infinite Illusion tokens, you may activate Preston any number of times

Results

• Exile any number of nonland permanents
• Infinite blinking of permanents
• Infinite ETB
• Infinite landfall
• Infinite LTB
• Infinite mana lands you control can produce