Is Nightmare legal in Standard, Modern, and Commander?

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

Nightmare

Q: What type of card is Nightmare?

Nightmare is a Creature — Nightmare Horse. Its oracle text reads: "Flying (This creature can't be blocked except by creatures with flying or reach.)Nightmare's power and toughness are each equal to the number of Swamps you control."

Creature — Nightmare Horse

Flying (This creature can't be blocked except by creatures with flying or reach.)<br>Nightmare's power and toughness are each equal to the number of Swamps you control.

Set Limited Edition Alpha

Rarity Rare

Artist Melissa A. Benson