Derevi, Empyrial Tactician, Cauldron of Souls, Aerith Gainsborough, and Phyrexian Altar

Prerequisites

• Derevi, Empyrial Tactician on the battlefield
• Cauldron of Souls on the battlefield
• Aerith Gainsborough on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Cauldron of Souls by tapping it, giving Derevi and Aerith persist until end of turn
2. Activate Phyrexian Altar by sacrificing Derevi
3. When Derevi dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
4. When Derevi enters the battlefield, it triggers, untapping Cauldron of Souls
5. Activate Phyrexian Altar by sacrificing Aerith
6. When Aerith dies, it triggers twice
7. Resolve Aerith's persist trigger, returning it from your graveyard to the battlefield with a -1/-1 counter on it
8. Resolve the second Aerith trigger, putting a +1/+1 counter on each legendary creature you control, thus removing the -1/-1 counters from Aerith and Derevi
9. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters on legendary creatures you control