Confidence:StrongSolidPlausibleTentativeSpeculative

• Clock of Omens

  4

  ArtifactC

  One-directional refresh: one card can untap permanents the other wants to reuse. Not self-sustaining on its own — the untapper has to keep showing up.
• Mist-Syndicate Naga

  2U

  Creature — Snake NinjaU

  Both cards produce the same kind of effect (shared token subtype).
• Intellectual Offering

  4U

  InstantU

  Intellectual Offering untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Aphelia, Viper Whisperer

  1B

  Legendary Creature — Gorgon AssassinBG

  Both cards produce the same kind of effect (shared token subtype).
• Unstoppable Plan

  2U

  EnchantmentU

  Unstoppable Plan untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Seedborn Muse

  3GG

  Creature — SpiritG

  Seedborn Muse untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Unwinding Clock

  4

  ArtifactC

  Unwinding Clock untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Sosuke's Summons

  2G

  SorceryG

  Both cards produce the same kind of effect (shared token subtype).
• Paradox Engine

  5

  Legendary ArtifactC

  Paradox Engine untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Dramatic Reversal

  1U

  InstantU

  Dramatic Reversal untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Blinkmoth Infusion

  12UU

  InstantU

  Blinkmoth Infusion untaps all (or many) permanents, refreshing Serpent Generator's tap activation.
• Fanatic of Rhonas

  1G

  Creature — Snake DruidG

  Both cards produce the same kind of effect (shared token subtype).
• Xyris, the Writhing Storm

  2GUR

  Legendary Creature — Snake LeviathanGRU

  Both cards produce the same kind of effect (shared token subtype).
• Hapatra, Vizier of Poisons

  BG

  Legendary Creature — Human ClericBG

  Both cards produce the same kind of effect (shared token subtype).
• Rhonas's Last Stand

  GG

  SorceryG

  Both cards produce the same kind of effect (shared token subtype).
• Hooded Hydra

  XGG

  Creature — Snake HydraG

  Both cards produce the same kind of effect (shared token subtype).
• Honored Hydra

  5G

  Creature — Snake HydraG

  Both cards produce the same kind of effect (shared token subtype).
• Snake Pit

  3G

  EnchantmentG

  Both cards produce the same kind of effect (shared token subtype).
• Llanowar Druid

  1G

  Creature — Elf DruidG

  Refuel loop: one card's payoff untaps your lands, paying for the other's activation again — repeatable every turn, and often infinite.
• Bestial Menace

  3GG

  SorceryG

  Both cards produce the same kind of effect (shared token subtype).
• Cobra Trap

  4GG

  Instant — TrapG

  Both cards produce the same kind of effect (shared token subtype).
• Ophiomancer

  2B

  Creature — Human ShamanB

  Both cards produce the same kind of effect (shared token subtype).
• Sinuous Striker

  2U

  Creature — Snake WarriorU

  Both cards produce the same kind of effect (shared token subtype).
• Tah-Crop Skirmisher

  1U

  Creature — Snake WarriorU

  Both cards produce the same kind of effect (shared token subtype).
• Patagia Viper

  3G

  Creature — SnakeGU

  Both cards produce the same kind of effect (shared token subtype).