Festival Combos
Havoc Festival + Wound Reflection
Havoc Festival + Archfiend of Despair
Emiel the Blessed + Earthcraft + Market Festival
Storm the Festival + Thassa's Oracle + Doomsday
Stone-Seeder Hierophant + Drownyard Temple + Market Festival
Combo result
Infinite lifegain. Infinite lifegain triggers. Infinite landfall triggers.
Prerequisites
Drownyard Temple in your graveyard. All other permanents on the battlefield. Stone-Seeder Hierophant does not have summoning sickness. Market Festival attached to any mana-producing land you control.