Is Scion of the Ur-Dragon legal in Standard, Modern, and Commander?

Scion of the Ur-Dragon is legal in: Modern, Legacy, Vintage, Commander.

Scion of the Ur-Dragon

Q: What type of card is Scion of the Ur-Dragon?

Scion of the Ur-Dragon is a Legendary Creature — Dragon Avatar. Its oracle text reads: "Flying {2}: Search your library for a Dragon permanent card and put it into your graveyard. If you do, Scion of the Ur-Dragon becomes a copy of that card until end of turn. Then shuffle."

Legendary Creature — Dragon Avatar

Flying

: Search your library for a Dragon permanent card and put it into your graveyard. If you do, Scion of the Ur-Dragon becomes a copy of that card until end of turn. Then shuffle.