Activate any number of other lands you control by tapping them, adding at least {3}{U}{B}{B}.
Activate Sylvan Safekeeper 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}{U}{B}{B}, 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 tapped.
When the lands enter the battlefield, Amulet of Vigor triggers that many times, untapping the lands.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite self-mill

Infinite mana lands you control can produce

Infinite landfall triggers

Put all land cards from your library and graveyard onto the battlefield

Lumra, Bellow of the Woods

Port of Karfell

Amulet of Vigor

Sylvan Safekeeper

Activate any number of other lands you control by tapping them, adding at least {3}{U}{B}{B}.
Activate Sylvan Safekeeper 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}{U}{B}{B}, 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.
Repeat.

Spelunking

Activate any number of other lands you control by tapping them, adding at least {3}{U}{B}{B}.
Activate Sylvan Safekeeper 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}{U}{B}{B}, 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 tapped.
When the lands enter the battlefield, Tiller Engine triggers that many times, untapping the lands.
Repeat.

Tiller Engine

If desired, activate any number of other mana-producing lands you control by tapping them, adding at least {1} for each land tapped this way.
Activate Squandered Resources by sacrificing a mana-producing land other than Port of Karfell, adding {U} or {B} if possible, or any other type of mana otherwise.
Repeat step 2 until you control no other mana-producing lands except Port of Karfell.
Activate Port of Karfell's second ability by paying {3}{U}{B}{B}, 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 Archelos.
Repeat.

Archelos, Lagoon Mystic

Squandered Resources

Combos with "Port of Karfell"