Polukranos, World Eater

Legendary Creature — Hydra

Polukranos, Unchained

Legendary Creature — Zombie Hydra

Liliana, Heretical Healer // Liliana, Defiant Necromancer

Legendary Creature — Human Cleric // Legendary Planeswalker — Liliana

Bonded Herdbeast // Plated Kilnbeast

Creature — Beast // Creature — Phyrexian Beast

Runo Stromkirk // Krothuss, Lord of the Deep

Legendary Creature — Vampire Cleric // Legendary Creature — Kraken Horror

Lone Rider // It That Rides as One

Creature — Human Knight // Creature — Eldrazi Horror

Wren's Run Hydra

Creature — Hydra

Hydroid Krasis

Creature — Jellyfish Hydra Beast

Zenos yae Galvus // Shinryu, Transcendent Rival

Legendary Creature — Human Noble Warrior // Legendary Creature — Dragon

Curse of Leeches // Leeching Lurker

Enchantment — Aura Curse // Creature — Leech Horror

Lifeblood Hydra

Creature — Hydra

Phyrexian Hydra

Creature — Phyrexian Hydra

The Dragon-Kami Reborn // Dragon-Kami's Egg

Enchantment — Saga // Enchantment Creature — Egg

Vincent Valentine // Galian Beast

Legendary Creature — Assassin // Legendary Creature — Werewolf Beast

Savageborn Hydra

Creature — Hydra

Kytheon, Hero of Akros // Gideon, Battle-Forged

Legendary Creature — Human Soldier // Legendary Planeswalker — Gideon

Bioessence Hydra

Creature — Hydra Mutant

Kessig Prowler // Sinuous Predator

Creature — Werewolf Horror // Creature — Eldrazi Werewolf

Vorinclex // The Grand Evolution

Legendary Creature — Phyrexian Praetor // Enchantment — Saga

Hydra Broodmaster

Creature — Hydra

Invasion of Ikoria // Zilortha, Apex of Ikoria

Battle — Siege // Legendary Creature — Dinosaur

Nyxborn Hydra

Enchantment Creature — Hydra

Serah Farron // Crystallized Serah

Legendary Creature — Human Citizen // Legendary Artifact

Heliod, the Radiant Dawn // Heliod, the Warped Eclipse

Legendary Enchantment Creature — God // Legendary Enchantment Creature — Phyrexian God

Kroxa and Kunoros

Legendary Creature — Elder Giant Dog

Rona, Herald of Invasion // Rona, Tolarian Obliterator

Legendary Creature — Human Wizard // Legendary Creature — Phyrexian Wizard

Domesticated Hydra

Creature — Hydra

Gnottvold Hermit // Chrome Host Hulk

Creature — Troll // Creature — Phyrexian Troll

Zaxara, the Exemplary

Legendary Creature — Nightmare Hydra

Grakmaw, Skyclave Ravager

Legendary Creature — Hydra Horror

Chandra, Fire of Kaladesh // Chandra, Roaring Flame

Legendary Creature — Human Shaman // Legendary Planeswalker — Chandra