Is A-Leyline of Resonance legal in Standard, Modern, and Commander?

A-Leyline of Resonance is legal in: Historic.

A-Leyline of Resonance

Q: What type of card is A-Leyline of Resonance?

A-Leyline of Resonance is an Enchantment. Its oracle text reads: "If this card is in your opening hand, you may begin the game with it on the battlefield. Whenever you cast an instant or sorcery spell that targets only a single creature you control, you may pay {1}. If you do, copy that spell. You may choose new targets for the copy."

Enchantment

If this card is in your opening hand, you may begin the game with it on the battlefield.

Whenever you cast an instant or sorcery spell that targets only a single creature you control, you may pay . If you do, copy that spell. You may choose new targets for the copy.