Is Dagger of the Worthy legal in Standard, Modern, and Commander?

Dagger of the Worthy is legal in: Modern, Pioneer, Legacy, Vintage, Commander.

Dagger of the Worthy

Q: What type of card is Dagger of the Worthy?

Dagger of the Worthy is an Artifact — Equipment. Its oracle text reads: "Equipped creature gets +2/+0 and has afflict 1. (Whenever it becomes blocked, defending player loses 1 life.) Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)"