17 cards where the text includes “mutate” and the color identity ≤ RUW

Archipelagore (IKO)
Cloudpiercer (IKO)
Cubwarden (IKO)
Dreamtail Heron (IKO)
Everquill Phoenix (IKO)
Huntmaster Liger (IKO)
Lore Drakkis (IKO)
Majestic Auricorn (IKO)
Mysterious Egg (IKO)
Pollywog Symbiote (IKO)
Porcuparrot (IKO)
Pouncing Shoreshark (IKO)
Regal Leosaur (IKO)
Sea-Dasher Octopus (IKO)
Souvenir Snatcher (C20)
Vadrok, Apex of Thunder (IKO)
Vulpikeet (IKO)

This search is finished. Now the real work can begin.