Soul of Windgrace + Waves of Aggression + Klauth, Unrivaled Ancient + Izzet Boilerworks
Soul of Windgrace
Waves of Aggression
Klauth, Unrivaled Ancient
Izzet Boilerworks
Infinite combat phasesInfinite landfall triggersInfinite magecraft triggersInfinite self-discard triggersInfinite storm countInfinite untap of most creatures you controlInfinite colored mana
How it works
Declare Klauth and Soul of Windgrace as attackers.
When they attack, Klauth and Soul of Windgrace trigger.
Resolve the Klauth trigger, adding at least nine mana that you will not lose this turn as steps and phases end.
Resolve the Soul of Windgrace trigger, returning Izzet Boilerworks from your graveyard to the battlefield tapped.
When Izzet Boilerworks enters, it triggers, returning itself from the battlefield to your hand.
In your next main phase, cast Waves of Aggression from your graveyard for its retrace cost by paying 3R/WR/W and discarding Izzet Boilerworks, causing you to untap all creatures that attacked this turn, and to get an additional combat and main phase after this one.