Magnanimous Magistrate, Doubling Season, Pollenbright Druid, and Phyrexian Altar

Prerequisites

• Magnanimous Magistrate on the battlefield
• Doubling Season on the battlefield
• Pollenbright Druid on the battlefield
• Phyrexian Altar on the battlefield
• Magnanimous Magistrate has at least three reprieve counters

Steps

1. Activate Phyrexian Altar by sacrificing Pollenbright Druid, adding one mana of any color
2. Pollenbright Druid dies, triggering Magnanimous Magistrate, causing you to remove two reprieve counters from Magnanimous Magistrate and return Pollenbright Druid from your graveyard to the battlefield
3. Pollenbright Druid enters the battlefield, causing you to proliferate, putting two reprieve counters on Magnanimous Magistrate
4. Repeat

Results

• Infinite colored mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite proliferate
• Infinite sacrifice triggers