Is Whispersteel Dagger legal in Standard, Modern, and Commander?

Whispersteel Dagger is legal in: Legacy, Vintage, Commander.

Whispersteel Dagger

Q: What type of card is Whispersteel Dagger?

Whispersteel Dagger is an Artifact — Equipment. Its oracle text reads: "Equipped creature gets +2/+0. Whenever equipped creature deals combat damage to a player, you may cast a creature spell from that player's graveyard this turn, and you may spend mana as though it were mana of any color to cast that spell. Equip {3}"

Artifact — Equipment

Equipped creature gets +2/+0.

Whenever equipped creature deals combat damage to a player, you may cast a creature spell from that player's graveyard this turn, and you may spend mana as though it were mana of any color to cast that spell.

Equip