Is Aeon Chronicler legal in Standard, Modern, and Commander?

Aeon Chronicler is legal in: Modern, Legacy, Vintage, Commander.

Aeon Chronicler

Q: What type of card is Aeon Chronicler?

Aeon Chronicler is a Creature — Avatar. Its oracle text reads: "Aeon Chronicler's power and toughness are each equal to the number of cards in your hand. Suspend X—{X}{3}{U}. X can't be 0. Whenever a time counter is removed from this card while it's exiled, draw a card."