Is Livio, Oathsworn Sentinel legal in Standard, Modern, and Commander?

Livio, Oathsworn Sentinel is legal in: Legacy, Vintage, Commander.

What type of card is Livio, Oathsworn Sentinel?

Livio, Oathsworn Sentinel is a Legendary Creature — Human Knight. Its oracle text reads: "{1}{W}: Choose another target creature. Its controller may exile it with an aegis counter on it. {2}{W}, {T}: Return all exiled cards with aegis counters on them to the battlefield under their owners' control. Partner (You can have two commanders if both have partner.) Power/Toughness: 2/2"