4 cards where the card types include “serpent” and (the card is available on Paper) and it’s legal in Standard

Biolume Egg // Biolume Serpent (Innistrad: Crimson Vow #49)
Biolume Egg // Biolume Serpent (Innistrad: Crimson Vow #49)
Bladecoil Serpent (The Brothers' War #229)
Invasion of Segovia // Caetus, Sea Tyrant of Segovia (March of the Machine #63)
Invasion of Segovia // Caetus, Sea Tyrant of Segovia (March of the Machine #63)
Tolarian Terror (Dominaria United #72)

The arc of my blade has carved a path of light to the end of these results.