Is Rite of Undoing legal in Standard, Modern, and Commander?

Rite of Undoing is legal in: Modern, Pioneer, Legacy, Vintage, Commander.

What type of card is Rite of Undoing?

Rite of Undoing is an Instant. Its oracle text reads: "Delve (Each card you exile from your graveyard while casting this spell pays for {1}.) Return target nonland permanent you control and target nonland permanent you don't control to their owners' hands."