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

Rimehorn Aurochs is legal in: Modern, Legacy, Vintage, Commander.

Rimehorn Aurochs

Q: What type of card is Rimehorn Aurochs?

Rimehorn Aurochs is a Snow Creature — Aurochs. Its oracle text reads: "Trample Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs. {2}{S}: Target creature blocks target creature this turn if able. ({S} can be paid with one mana from a snow source.)"