Is Blanket of Night legal in Standard, Modern, and Commander?

Blanket of Night is legal in: Legacy, Vintage, Commander.

What type of card is Blanket of Night?

Blanket of Night is an Enchantment. Its oracle text reads: "Each land is a Swamp in addition to its other land types."

Enchantment

Each land is a Swamp in addition to its other land types.

Set Visions

Rarity Uncommon

Artist Cliff Nielsen

Enchantment Commander Legacy Vintage