Is Inspiring Unicorn legal in Standard, Modern, and Commander?

Inspiring Unicorn is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Inspiring Unicorn

Q: What type of card is Inspiring Unicorn?

Inspiring Unicorn is a Creature — Unicorn. Its oracle text reads: "Whenever this creature attacks, creatures you control get +1/+1 until end of turn. *There are two lives: the life you live before you see a unicorn, and the life you live after.* Power/Toughness: 2/2"