Is Sovereigns of Lost Alara legal in Standard, Modern, and Commander?

Sovereigns of Lost Alara is legal in: Modern, Legacy, Vintage, Commander.

Sovereigns of Lost Alara

Q: What type of card is Sovereigns of Lost Alara?

Sovereigns of Lost Alara is a Creature — Spirit. Its oracle text reads: "Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.) Whenever a creature you control attacks alone, you may search your library for an Aura card that could enchant that creature, put it onto the battlefield attached to that creature, then shuffle."

Creature — Spirit

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Whenever a creature you control attacks alone, you may search your library for an Aura card that could enchant that creature, put it onto the battlefield attached to that creature, then shuffle.

Set Ultimate Masters

Rarity Rare

Mana Value 6

Artist Donato Giancola

Collector # 207

Scryfall Gatherer