Preston, the Vanisher, Delney, Streetwise Lookout, Sefris of the Hidden Ways, Umbral Collar Zealot, and Bloodboil Sorcerer

Prerequisites

• Preston, the Vanisher on the battlefield
• Delney, Streetwise Lookout on the battlefield
• Sefris of the Hidden Ways on the battlefield
• Umbral Collar Zealot on the battlefield
• Bloodboil Sorcerer 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 Bloodboil Sorcerer from your graveyard onto the battlefield
5. When Bloodboil Sorcerer enters, it triggers once and Preston triggers twice due to Delney
6. Holding priority, activate Umbral Collar Zealot by sacrificing Bloodboil Sorcerer
7. Resolve a Preston trigger, creating a token copy of Bloodboil Sorcerer that is a 0/1 Illusion
8. When the Bloodboil Sorcerer token enters, it triggers twice due to Delney
9. Resolve the Bloodboil Sorcerer token triggers, venturing into Undercity twice
10. Resolve the second Preston trigger from step 5, creating a token copy of Bloodboil Sorcerer that is a 0/1 Illusion
11. Repeat steps 8 and 9 one additional time
12. Resolve the Bloodboil Sorcerer 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
• Infinite surveil
• 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