Confidence:StrongSolidPlausibleTentativeSpeculative

• Roaming Throne

  4

  Artifact Creature — GolemC

  Roaming Throne makes First Responder'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 First Responder'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 First Responder's triggered ability trigger an additional time — each time it fires, you get it twice. Value, not a loop.
• Ajani, Nacatl Pariah // Ajani, Nacatl Avenger

  1W

  Legendary Creature — Cat Warrior // Legendary Planeswalker — AjaniRW

  First Responder bounces a permanent, enabling Ajani, Nacatl Pariah's recast / spell-cast trigger.
• Agrus Kos, Spirit of Justice

  2RW

  Legendary Creature — Spirit DetectiveRW

  First Responder bounces a permanent, enabling Agrus Kos, Spirit of Justice's recast / spell-cast trigger.
• Phlage, Titan of Fire's Fury

  1RW

  Legendary Creature — Elder GiantRW

  First Responder bounces a permanent, enabling Phlage, Titan of Fire's Fury's recast / spell-cast trigger.
• Odric, Blood-Cursed

  1RW

  Legendary Creature — Vampire SoldierRW

  First Responder bounces a permanent, enabling Odric, Blood-Cursed's recast / spell-cast trigger.
• Emeritus of Truce // Swords to Plowshares

  1WWW

  Creature — Cat Cleric // InstantW

  First Responder bounces a permanent, enabling Emeritus of Truce's recast / spell-cast trigger.
• Serene Sleuth

  1W

  Creature — Human DetectiveW

  First Responder bounces a permanent, enabling Serene Sleuth's recast / spell-cast trigger.
• Wildfire Devils

  3R

  Creature — DevilR

  First Responder bounces a permanent, enabling Wildfire Devils's recast / spell-cast trigger.
• Solitude

  3WW

  Creature — Elemental IncarnationW

  First Responder bounces a permanent, enabling Solitude's recast / spell-cast trigger.
• Uro, Titan of Nature's Wrath

  1GU

  Legendary Creature — Elder GiantGU

  First Responder bounces a permanent, enabling Uro, Titan of Nature's Wrath's recast / spell-cast trigger.
• Orcish Bowmasters

  1B

  Creature — Orc ArcherB

  First Responder bounces a permanent, enabling Orcish Bowmasters's recast / spell-cast trigger.
• Undermountain Adventurer

  3G

  Creature — Giant WarriorG

  First Responder bounces a permanent, enabling Undermountain Adventurer's recast / spell-cast trigger.
• Omnath, Locus of Creation

  RGWU

  Legendary Creature — ElementalGRUW

  First Responder bounces a permanent, enabling Omnath, Locus of Creation's recast / spell-cast trigger.
• Phyrexian Dreadnought

  1

  Artifact Creature — Phyrexian DreadnoughtC

  First Responder bounces a permanent, enabling Phyrexian Dreadnought's recast / spell-cast trigger.
• Regal Sliver

  3W

  Creature — SliverW

  First Responder bounces a permanent, enabling Regal Sliver's recast / spell-cast trigger.
• Izoni, Center of the Web

  4BG

  Legendary Creature — Elf DetectiveBG

  First Responder bounces a permanent, enabling Izoni, Center of the Web's recast / spell-cast trigger.
• Bruse Tarl, Roving Rancher

  2RW

  Legendary Creature — Human WarriorRW

  First Responder bounces a permanent, enabling Bruse Tarl, Roving Rancher's recast / spell-cast trigger.
• Sygg, Wanderwine Wisdom // Sygg, Wanderbrine Shield

  1U

  Legendary Creature — Merfolk Wizard // Legendary Creature — Merfolk RogueUW

  First Responder bounces a permanent, enabling Sygg, Wanderwine Wisdom's recast / spell-cast trigger.
• Raven Eagle

  2B

  Creature — Bird AssassinB

  First Responder bounces a permanent, enabling Raven Eagle's recast / spell-cast trigger.
• Reanimate

  B

  SorceryB

  Reanimate puts First Responder onto the battlefield from a graveyard without casting it, so its mana cost is never paid.
• Rampart Architect

  3G

  Creature — Elephant AdvisorG

  First Responder bounces a permanent, enabling Rampart Architect's recast / spell-cast trigger.
• Aven Interrupter

  1WW

  Creature — Bird RogueW

  First Responder bounces a permanent, enabling Aven Interrupter's recast / spell-cast trigger.
• Bebop, Skull & Crossbones

  1B

  Legendary Creature — Boar MutantB

  First Responder bounces a permanent, enabling Bebop, Skull & Crossbones's recast / spell-cast trigger.