Is Gandalf the White legal in Standard, Modern, and Commander?

Gandalf the White is legal in: Modern, Legacy, Vintage, Commander, Historic.

Gandalf the White

Q: What type of card is Gandalf the White?

Gandalf the White is a Legendary Creature — Avatar Wizard. Its oracle text reads: "Flash You may cast legendary spells and artifact spells as though they had flash. If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time."

Legendary Creature — Avatar Wizard

Flash

You may cast legendary spells and artifact spells as though they had flash.

If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Set The Lord of the Rings: Tales of Middle-earth

Rarity Mythic Rare

Mana Value 5

Artist Magali Villeneuve

Collector # 19

Scryfall Gatherer