Is Sunken Palace legal in Standard, Modern, and Commander?

Sunken Palace is legal in: Legacy, Vintage, Commander.

What type of card is Sunken Palace?

Sunken Palace is a Land — Cave. Its oracle text reads: "This land enters tapped. {T}: Add {U}. {1}{U}, {T}, Exile seven cards from your graveyard: Add {U}. When you spend this mana to cast a spell or activate an ability, copy that spell or ability. You may choose new targets for the copy. (Mana abilities can't be copied.)"

Sunken Palace

Land — Cave

This land enters tapped.

: Add .

, , Exile seven cards from your graveyard: Add . When you spend this mana to cast a spell or activate an ability, copy that spell or ability. You may choose new targets for the copy. (Mana abilities can't be copied.)