Lumra, Bellow of the Woods | Port of Karfell | Tiller Engine

(and one other card)

Lumra in your graveyard.
All other permanents on the battlefield.
You can produce at least ({3} magic symbol) ({U} magic symbol) ({B} magic symbol) ({B} magic symbol) between sacrificing lands excluding
Port of Karfell to
Squandered Resources and/or by tapping those lands for mana.

If desired, activate any number of other mana-producing lands you control by tapping them, adding at least ({1} magic symbol) for each land tapped this way.
Activate
Squandered Resources by sacrificing a mana-producing land other than
Port of Karfell, adding ({U} magic symbol) or ({B} magic symbol) 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} magic symbol) ({U} magic symbol) ({B} magic symbol) ({B} magic symbol) , 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.