Is Sylvia Brightspear legal in Standard, Modern, and Commander?

Sylvia Brightspear is legal in: Legacy, Vintage, Commander.

Sylvia Brightspear

Q: What type of card is Sylvia Brightspear?

Sylvia Brightspear is a Legendary Creature — Human Knight. Its oracle text reads: "Partner with Khorvath Brightflame (When this creature enters, target player may put Khorvath into their hand from their library, then shuffle.) Double strike Dragons your team controls have double strike. Power/Toughness: 2/2"