Is Lamentation legal in Standard, Modern, and Commander?

Lamentation is legal in: Legacy, Vintage, Commander.

What type of card is Lamentation?

Lamentation is a Creature — Elemental Incarnation. Its oracle text reads: "When this creature enters, destroy target creature an opponent controls. You gain 3 life. Encore {6}{B}{B} ({6}{B}{B}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)"

Lamentation

Creature — Elemental Incarnation

When this creature enters, destroy target creature an opponent controls. You gain 3 life.

Encore (, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)