Is The Lady of Otaria legal in Standard, Modern, and Commander?

The Lady of Otaria is legal in: Legacy, Vintage, Commander.

The Lady of Otaria

Q: What type of card is The Lady of Otaria?

The Lady of Otaria is a Legendary Creature — Avatar. Its oracle text reads: "You may tap three untapped Dwarves you control rather than pay this spell's mana cost. At the beginning of each end step, if a land you controlled was put into a graveyard from the battlefield this turn, reveal the top four cards of your library. You may put any number of Dwarf cards from among them into your hand. Put the rest on the bottom of your library in a random order. Power/Toughness: 5/5"

Legendary Creature — Avatar

You may tap three untapped Dwarves you control rather than pay this spell's mana cost.

At the beginning of each end step, if a land you controlled was put into a graveyard from the battlefield this turn, reveal the top four cards of your library. You may put any number of Dwarf cards from among them into your hand. Put the rest on the bottom of your library in a random order.

Power/Toughness: 5/5

Set Dominaria United Commander

Rarity Mythic Rare

Mana Value 5

Artist Scott Murphy

Collector # 35

Scryfall