The monarch mechanic provides card advantage and interesting table dynamics
Beseech the Mirror Bile-Vial Boggart Billowing Shriekmass Binding Negotiation Bitter Triumph Bitterbloom Bearer Black Cat, Cunning Thief Black Mage's Rod Black Widow, Super Spy Blacksnag Buzzard Blade of the Swarm Blasphemous Edict Blight Rot Blighted Blackthorn Blood Hustler Bloodghast Bloodletter of Aclazotz Bloodline Bidding
Remember, kids, Medusa is the name of a type of creature called a Gorgon
Finneon may not have much HP, but its Elegant Swim can help it survive longer if you land on heads
Secret Arcade, Nylea's Colossus, Thoughtrender Lamia, Ondu Spiritdancer, and Sphere of Safety give you huge advantages with tons of +1/+1 counters, forced discard, or the hinderance of attacks to name a few
This also ties in with Pokemon game lore where Eevee is often found in grassy areas