Activate Undermountain Adventurer by tapping it, adding six {G}.
Activate Staff of Domination's third ability by paying {3} and tapping it, untapping Undermountain Adventurer.
Activate Staff of Domination's first ability by paying {1}, untapping it.
Repeat.

Infinite card draw

Infinite draw triggers

Infinite lifegain

Infinite lifegain triggers

Infinite mana creatures you control can produce

Infinite untap of creatures you control

Infinite green mana

Staff of Domination

Undermountain Adventurer

Activate Undermountain Adventurer by tapping it, adding at least {G}{G}.
Activate Scryb Ranger by returning it from the battlefield to your hand, untapping Undermountain Adventurer.
Cast Scryb Ranger by paying {1}{G}.
Repeat.

Infinite LTB

Infinite ETB

Infinite storm count

Infinite landfall triggers

Ashaya, Soul of the Wild

Scryb Ranger

Activate Marvin using Undermountain Adventurer's ability by tapping it, adding at least {G}{G}.
Activate Marvin using Pili-Pala's ability by paying {2} and untapping it, adding one mana of any color.
Repeat.

Infinite colored mana

Marvin, Murderous Mimic

Pili-Pala

Activate Undermountain Adventurer by tapping it, adding at least {G}{G}.
Cast Wirewood Symbiote by paying {G}.
Activate Mirror Entity by paying {1}, giving creatures you control all creature types and base power and toughness 1/1 until end of turn.
Activate Wirewood Symbiote by returning it from the battlefield to your hand, untapping Undermountain Adventurer.
Repeat.

Infinitely large creatures you control until end of turn

Wirewood Symbiote

Mirror Entity

Activate Undermountain Adventurer by tapping it, adding six {G}.
Activate Chrome Dome by paying {5}, creating a token copy of Sewer-veillance Cam.
When the Sewer-veillance Cam token enters, it triggers, untapping Undermountain Adventurer.
Repeat.

Infinite copies of artifacts you control with haste

Infinite creature tokens with haste

Infinite death triggers

Infinite sacrifice triggers

Chrome Dome

Sewer-veillance Cam

Activate Rex using Undermountain Adventurer's ability by tapping it, adding at least {G}{G}.
Activate Rex using Pili-Pala's ability by paying {2} and untapping it, adding one mana of any color.
Repeat.

Rex, Cyber-Hound

Combos with "Undermountain Adventurer"