Is Boreas Charger legal in Standard, Modern, and Commander?

Boreas Charger is legal in: Legacy, Vintage, Commander.

Boreas Charger

Q: What type of card is Boreas Charger?

Boreas Charger is a Creature — Pegasus. Its oracle text reads: "Flying When this creature leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle."

Creature — Pegasus

Flying

When this creature leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle.

Set Crimson Vow Commander

Rarity Rare

Mana Value 3

Artist Christine Choi

Collector # 79

Scryfall Gatherer