Is Aurochs Herd legal in Standard, Modern, and Commander?

Aurochs Herd is legal in: Modern, Legacy, Vintage, Commander, Pauper.

Aurochs Herd

Q: What type of card is Aurochs Herd?

Aurochs Herd is a Creature — Aurochs. Its oracle text reads: "Trample When this creature enters, you may search your library for an Aurochs card, reveal it, put it into your hand, then shuffle. Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs."