Is Llanowar Cavalry legal in Standard, Modern, and Commander?

Llanowar Cavalry is legal in: Legacy, Vintage, Commander, Pauper.

Llanowar Cavalry

Q: What type of card is Llanowar Cavalry?

Llanowar Cavalry is a Creature — Human Soldier. Its oracle text reads: "{W}: This creature gains vigilance until end of turn. *For the first time, elves welcomed Benalish soldiers into the forest with something other than arrows.* Power/Toughness: 1/4"