Is Forerunner of the Legion legal in Standard, Modern, and Commander?

Forerunner of the Legion is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Forerunner of the Legion

Q: What type of card is Forerunner of the Legion?

Forerunner of the Legion is a Creature — Vampire Knight. Its oracle text reads: "When this creature enters, you may search your library for a Vampire card, reveal it, then shuffle and put that card on top. Whenever another Vampire you control enters, target creature gets +1/+1 until end of turn. Power/Toughness: 2/2"