Is Sphinx of the Second Sun legal in Standard, Modern, and Commander?

Sphinx of the Second Sun is legal in: Legacy, Vintage, Commander.

Sphinx of the Second Sun

Q: What type of card is Sphinx of the Second Sun?

Sphinx of the Second Sun is a Creature — Sphinx. Its oracle text reads: "Flying At the beginning of each of your postcombat main phases, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.) *He watches in silence as the shadows shift, bringing Amonkhet ever nearer to the Hour of Revelation.* Power/Toughness: 6/6"

Creature — Sphinx

Flying

At the beginning of each of your postcombat main phases, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.)

*He watches in silence as the shadows shift, bringing Amonkhet ever nearer to the Hour of Revelation.*

Power/Toughness: 6/6

Set Murders at Karlov Manor Commander

Rarity Mythic Rare

Mana Value 8

Artist Antonio José Manzanedo

Collector # 118

Scryfall