Is Everquill Phoenix legal in Standard, Modern, and Commander?

Everquill Phoenix is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Everquill Phoenix

Q: What type of card is Everquill Phoenix?

Everquill Phoenix is a Creature — Phoenix. Its oracle text reads: "Mutate {3}{R} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flying Whenever this creature mutates, create a red artifact token named Feather with "{1}, Sacrifice this token: Return target Phoenix card from your graveyard to the battlefield tapped.""

Creature — Phoenix

Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Flying

Whenever this creature mutates, create a red artifact token named Feather with ", Sacrifice this token: Return target Phoenix card from your graveyard to the battlefield tapped."