Is Court Hussar legal in Standard, Modern, and Commander?

Court Hussar is legal in: Modern, Legacy, Vintage, Commander, Pauper.

Court Hussar

Q: What type of card is Court Hussar?

Court Hussar is a Creature — Vedalken Knight. Its oracle text reads: "Vigilance When this creature enters, look at the top three cards of your library, then put one of them into your hand and the rest on the bottom of your library in any order. When this creature enters, sacrifice it unless {W} was spent to cast it."

Creature — Vedalken Knight

Vigilance

When this creature enters, look at the top three cards of your library, then put one of them into your hand and the rest on the bottom of your library in any order.

When this creature enters, sacrifice it unless was spent to cast it.