Is Possessed Aven legal in Standard, Modern, and Commander?

Possessed Aven is legal in: Legacy, Vintage, Commander.

Possessed Aven

Q: What type of card is Possessed Aven?

Possessed Aven is a Creature — Bird Soldier Horror. Its oracle text reads: "Flying Threshold — As long as seven or more cards are in your graveyard, this creature gets +1/+1, is black, and has "{2}{B}, {T}: Destroy target blue creature." Power/Toughness: 3/3"