Is Skyblade's Boon legal in Standard, Modern, and Commander?

Skyblade's Boon is legal in: Modern, Legacy, Vintage, Commander, Historic.

What type of card is Skyblade's Boon?

Skyblade's Boon is an Enchantment — Aura. Its oracle text reads: "Enchant creature Enchanted creature gets +1/+1 and has flying. {2}{W}: Return Skyblade's Boon to its owner's hand. Activate only if Skyblade's Boon is on the battlefield or in your graveyard."