Toph, the First Metalbender + Urborg, Tomb of Yawgmoth + Staff of Domination + Caged Sun
Toph, the First Metalbender
Urborg, Tomb of Yawgmoth
Staff of Domination
Caged Sun
Infinite lifegain triggersInfinite lifegainDraw the gameInfinite card drawInfinite untap of creatures you controlInfinite draw triggersInfinite mana creatures you control can produceInfinite black mana
How it works
Activate Staff of Domination by tapping it, adding as it's a Swamp land due to Toph and Urborg
Caged Sun triggers, adding .
Activate Staff of Domination's first ability by paying 1, untapping it.
Repeat.
Activate a land by tapping it, adding at least one mana of the color named by Caged Sun.
Caged Sun triggers, adding one mana of that color.
Caged Sun triggers again, as it is a land due to Toph, adding one mana of that color.
Step 3 repeats in a mandatory infinite loop, causing the game to end in a draw.