Great Oak Guardian, Pulsemage Advocate, and Altar of Dementia

Prerequisites

• Great Oak Guardian on the battlefield
• Pulsemage Advocate on the battlefield
• Altar of Dementia on the battlefield
• Pulsemage Advocate does not have summoning sickness

Steps

1. Activate Altar of Dementia by sacrificing Great Oak Guardian, causing target opponent to mill four cards
2. Activate Pulsemage Advocate by tapping it and putting three cards from an opponent's graveyard into their owner's hand, returning Great Oak Guardian from your graveyard to the battlefield
3. Great Oak Guardian enters the battlefield, untapping all creatures and giving creatures you control +2/+2 until end of turn
4. Repeat

Results

• Infinite card draw for opponents
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinitely large creatures until end of turn
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of creatures you control
• Infinitely large creatures you control until end of turn