Is Spellshift legal in Standard, Modern, and Commander?

Spellshift is legal in: Modern, Legacy, Vintage, Commander.

Spellshift

Q: What type of card is Spellshift?

Spellshift is an Instant. Its oracle text reads: "Counter target instant or sorcery spell. Its controller reveals cards from the top of their library until they reveal an instant or sorcery card. That player may cast that card without paying its mana cost. Then the player shuffles."

Instant

Counter target instant or sorcery spell. Its controller reveals cards from the top of their library until they reveal an instant or sorcery card. That player may cast that card without paying its mana cost. Then the player shuffles.

Set Planar Chaos

Rarity Rare

Mana Value 4

Artist Stephen Tappin

Collector # 47

Scryfall Gatherer