Lumra, Bellow of the Woods + Port of Karfell + Spelunking + Trenching Steed
Lumra, Bellow of the Woods
Port of Karfell
Spelunking
Trenching Steed
Infinite death triggersInfinite creature ETBInfinite landfall triggersInfinite creature LTBInfinite mana lands you control can produceInfinite creature sacrifice triggersInfinite self-millPut all land cards from your library and graveyard onto the battlefieldInfinite card drawInfinite draw triggers
How it works
Activate any number of other lands you control by tapping them, adding at least 3.
Activate Trenching Steed by sacrificing a land other than Port of Karfell.
Repeat step 2 until you control no other lands except Port of Karfell.
Activate Port of Karfell's second ability by paying 3, tapping and sacrificing it, causing you to mill four cards and return Lumra from your graveyard to the battlefield tapped.
Lumra enters the battlefield and dies as a state-based action due to having 0 toughness.
Lumra's enter-the-battlefield ability triggers, causing you to mill four cards and return all land cards from your graveyard to the battlefield untapped due to Spelunking.