Is Mobilized District legal in Standard, Modern, and Commander?

Mobilized District is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Mobilized District

Q: What type of card is Mobilized District?

Mobilized District is a Land. Its oracle text reads: "{T}: Add {C}. {4}: This land becomes a 3/3 Citizen creature with vigilance until end of turn. It's still a land. This ability costs {1} less to activate for each legendary creature and planeswalker you control."

Land

: Add .

: This land becomes a 3/3 Citizen creature with vigilance until end of turn. It's still a land. This ability costs less to activate for each legendary creature and planeswalker you control.