Is Magosi, the Waterveil legal in Standard, Modern, and Commander?

Magosi, the Waterveil is legal in: Modern, Legacy, Vintage, Commander.

What type of card is Magosi, the Waterveil?

Magosi, the Waterveil is a Land. Its oracle text reads: "This land enters tapped. {T}: Add {U}. {U}, {T}: Put an eon counter on this land. Skip your next turn. {T}, Remove an eon counter from this land and return it to its owner's hand: Take an extra turn after this one."