Soul of Windgrace + Waves of Aggression + Klauth, Unrivaled Ancient
Soul of Windgrace
Waves of Aggression
Klauth, Unrivaled Ancient
Infinite colored mana that can only be spent to cast spellsInfinite combat phasesInfinite magecraft triggersInfinite self-discard triggersInfinite storm count
How it works
Declare Klauth and Soul of Windgrace as attackers, triggering their abilities.
Resolve the Klauth trigger, adding at least 7R/WR/W that can only be spent to cast spells.
Resolve the Soul of Windgrace trigger, returning a land card from your graveyard to the battlefield tapped.
Move to your postcombat main phase.
Cast Waves of Aggression from your graveyard for its retrace cost by paying 3R/WR/W and discarding a land card, causing you to untap all creatures that attacked this turn, and to get an additional combat and main phase after this one.