Is Nimbus Champion legal in Standard, Modern, and Commander?

Nimbus Champion is legal in: Legacy, Vintage, Commander.

Nimbus Champion

Q: What type of card is Nimbus Champion?

Nimbus Champion is a Creature — Avatar Warrior. Its oracle text reads: "Flying Whenever this creature attacks, you may return target creature to its owner's hand if that creature's power is less than or equal to the number of Warriors your team controls. Power/Toughness: 4/4"

Creature — Avatar Warrior

Flying

Whenever this creature attacks, you may return target creature to its owner's hand if that creature's power is less than or equal to the number of Warriors your team controls.

Power/Toughness: 4/4

Set Battlebond

Rarity Uncommon

Mana Value 6

Artist Anastasia Ovchinnikova

Collector # 37

Scryfall