Zaxara, the Exemplary [Dominaria United Commander] Hydra exile up to one target

exile up to one target legendary or Rat card from your graveyard and copy it

but I believe a more mundane power source might suffice

The Rime of the Ancient Mariner

After this phase

Set: Dominaria Remastered Type: Land Rarity: Rare Gemstone Mine comes into play with three mining counters on it

Zaxara, the Exemplary [Dominaria United Commander] Hydra exile up to one targetSet: Dominaria United Commander Type: Legendary Creature Nightmare Hydra Rarity: Mythic Cost: {1}{B}{G}{U} Deathtouch {T}: Add two mana of any one color. Whenever you cast a spell with {X} in its mana cost, create a 0 0 green Hydra creature token, then put X +1 +1 counters on it.