Confidence:StrongSolidPlausibleTentativeSpeculative

• Sewer-veillance Cam✓

  U

  ArtifactU

  Untap loop: each side can untap what the other taps — a genuine mutual refresh engine.
• Copperhorn Scout

  G

  Creature — Elf ScoutG

  Copperhorn Scout untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Legion Extruder

  1R

  ArtifactR

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• White Plume Adventurer

  2W

  Creature — Orc ClericW

  White Plume Adventurer untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Jace, Ingenious Mind-Mage

  4UU

  Legendary Planeswalker — JaceU

  Jace, Ingenious Mind-Mage untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Aggravated Assault

  2R

  EnchantmentR

  Aggravated Assault untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Roxanne, Starfall Savant

  3RG

  Legendary Creature — Cat DruidGR

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• The Thirteenth Doctor

  1GU

  Legendary Creature — Time Lord DoctorGU

  The Thirteenth Doctor untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Veteran Beastrider

  1GW

  Creature — Human KnightGW

  Veteran Beastrider untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Intruder Alarm✓

  2U

  EnchantmentU

  Intruder Alarm untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Dubious Delicacy

  2B

  Artifact — FoodB

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Drumbellower

  2W

  Creature — SpiritW

  Drumbellower untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Gideon, Martial Paragon

  4W

  Legendary Planeswalker — GideonW

  Gideon, Martial Paragon untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Loki's Scepter

  2R

  Legendary ArtifactR

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Polygraph Orb

  4B

  ArtifactB

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Dazzling Theater // Prop Room

  3W2W

  Enchantment — Room // Enchantment — RoomW

  Dazzling Theater untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Intellectual Offering

  4U

  InstantU

  Intellectual Offering untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Grim Bauble

  B

  ArtifactB

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Prophet of Kruphix

  3GU

  Creature — Human WizardGU

  Prophet of Kruphix untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Éomer, Marshal of Rohan

  2RR

  Legendary Creature — Human KnightR

  Éomer, Marshal of Rohan untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Inverted Iceberg // Iceberg Titan

  1U

  Artifact // Artifact Creature — GolemU

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Vessel of Endless Rest

  3

  ArtifactC

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.
• Ivorytusk Fortress

  2WBG

  Creature — ElephantBGW

  Ivorytusk Fortress untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Unstoppable Plan

  2U

  EnchantmentU

  Unstoppable Plan untaps all (or many) permanents, refreshing Goblin Welder's tap activation.
• Glider Staff

  2W

  Artifact — EquipmentW

  Recursion engine: one card can reanimate repeatedly (an activated ability), and the other is a creature worth bringing back again and again. Real, repeatable value — not an infinite loop on its own.