Is Season of Loss legal in Standard, Modern, and Commander?

Season of Loss is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

What type of card is Season of Loss?

Season of Loss is a Sorcery. Its oracle text reads: "Choose up to five {P} worth of modes. You may choose the same mode more than once. {P} — Each player sacrifices a creature of their choice. {P}{P} — Draw a card for each creature that died under your control this turn. {P}{P}{P} — Each opponent loses X life, where X is the number of creature cards in your graveyard."