Preston, the Vanisher, Delney, Streetwise Lookout, Sefris of the Hidden Ways, Phyrexian Altar, and Avenging Hunter

Prerequisites

• Preston, the Vanisher on the battlefield
• Delney, Streetwise Lookout on the battlefield
• Sefris of the Hidden Ways on the battlefield
• Phyrexian Altar on the battlefield
• Avenging Hunter in the graveyard

Steps

1. Complete a dungeon
2. Sefris' second ability triggers twice due to Delney
3. Resolve the first trigger, returning up to one other creature from your graveyard to the battlefield
4. Resolve the second trigger, returning Avenging Hunter from your graveyard onto the battlefield
5. When Avenging Hunter enters, it triggers once and Preston triggers twice due to Delney
6. Holding priority, activate Phyrexian Altar by sacrificing Avenging Hunter
7. Resolve a Preston trigger, creating a token copy of Avenging Hunter that is a 0/1 Illusion
8. When the Avenging Hunter token enters, it triggers twice due to Delney
9. Resolve the Avenging Hunter token triggers, venturing into Undercity twice
10. Resolve the second Preston trigger from step 5, creating a token copy of Avenging Hunter that is a 0/1 Illusion
11. Repeat steps 8 and 9 one additional time
12. Resolve the Avenging Hunter trigger from step 5, venturing into Undercity and completing Undercity
13. Repeat from step 2

Results

• Infinite +1/+1 counters on creatures you control
• Infinite ETB
• Infinite LTB
• Infinite Treasure tokens
• Infinite card draw
• Infinite colored mana
• Infinite creature tokens
• Infinite death triggers
• Infinite draw triggers
• Infinite sacrifice triggers
• Near-infinite lifeloss
• Put all basic lands from your library into your hand
• Put all creature cards from your library onto the battlefield
• Return most creature cards from your graveyard onto the battlefield