Confidence:StrongSolidPlausibleTentativeSpeculative

• Roaming Throne

  4

  Artifact Creature — GolemC

  Roaming Throne makes Herald of Serra's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Mirror Room // Fractured Realm

  2U5UU

  Enchantment — Room // Enchantment — RoomU

  Mirror Room makes Herald of Serra's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Wizard's Staff

  1U

  Artifact — EquipmentU

  Wizard's Staff makes Herald of Serra's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.