Delney, Streetwise Lookout + Phantom Train + Preston, the Vanisher + and 2 others

GWUB identity

Commander legal

The 5 combo pieces

• Delney, Streetwise Lookout
• Phantom Train
• Preston, the Vanisher
• Sefris of the Hidden Ways
• Undermountain Adventurer

What must be in place

You are able to complete a dungeon.

How to execute it

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 Undermountain Adventurer from your graveyard onto the battlefield.
5. When Undermountain Adventurer enters, it triggers once and Preston triggers twice due to Delney.
6. Holding priority, activate Phantom Train by sacrificing Undermountain Adventurer.
7. Resolve a Preston trigger, creating a token copy of Undermountain Adventurer that is a 0/1 Illusion.
8. When the Undermountain Adventurer token enters, it triggers twice due to Delney.
9. Resolve the Undermountain Adventurer token triggers, venturing into Undercity twice.
10. Resolve the second Preston trigger from step 5, creating a token copy of Undermountain Adventurer that is a 0/1 Illusion.
11. Repeat steps 8 and 9 one additional time.
12. Resolve the Undermountain Adventurer trigger from step 5, venturing into Undercity and completing Undercity.
13. Repeat from step 2.

What the combo produces

• Infinite +1/+1 counters on creatures you control
• Infinite card draw
• Infinite colored mana
• Infinite creature LTB
• Infinite creature tokens
• Infinite death triggers
• Infinite draw triggers
• Infinite ETB
• Infinite sacrifice triggers
• Infinite Treasure tokens
• 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