Is Isengard Unleashed legal in Standard, Modern, and Commander?

Isengard Unleashed is legal in: Legacy, Vintage, Commander.

Isengard Unleashed

Q: What type of card is Isengard Unleashed?

Isengard Unleashed is a Sorcery. Its oracle text reads: "Damage can't be prevented this turn. If a source you control would deal damage this turn to an opponent or a permanent an opponent controls, it deals triple that damage instead. Flashback {4}{R}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)"

Sorcery

Damage can't be prevented this turn. If a source you control would deal damage this turn to an opponent or a permanent an opponent controls, it deals triple that damage instead.

Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)