Underworld Breach | Squandered Resources | Splendid Reclamation

(and one other card)

Underworld Breach and
Squandered Resources on the battlefield.
Splendid Reclamation and
Windfall in hand or in your graveyard.
A player has at least six cards in hand, not including
Windfall if its in your hand.
You control at least seven lands, of which one can tap to produce ({U} magic symbol) and another can tap to produce ({G} magic symbol) .
If
Windfall is in your graveyard, you have three other cards in your graveyard excluding it and
Splendid Reclamation if it's in your graveyard.

Activate
Squandered Resources by sacrificing at least seven lands, adding ({5} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Cast
Windfall either from your hand by paying ({2} magic symbol) ({U} magic symbol) , or from your graveyard for its escape cost by paying ({2} magic symbol) ({U} magic symbol) and exiling three nonland cards except
Splendid Reclamation from your graveyard, causing each player to discard their hand and draw cards equal to the greatest number a player discarded this way.
Cast
Splendid Reclamation from your graveyard for its escape cost by paying ({3} magic symbol) ({G} magic symbol) and exiling three nonland cards except
Windfall from your graveyard, returning all land cards from your graveyard to the battlefield tapped.
Repeat.
Depending on the number of cards in a player's hand and/or in your graveyard when
Windfall resolves, you may be able to omit casting it during an iteration.