Is Steward of Solidarity legal in Standard, Modern, and Commander?

Steward of Solidarity is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Steward of Solidarity

Q: What type of card is Steward of Solidarity?

Steward of Solidarity is a Creature — Human Warrior. Its oracle text reads: "{T}, Exert Steward of Solidarity: Create a 1/1 white Warrior creature token with vigilance. (An exerted creature won't untap during your next untap step.)"

Creature — Human Warrior

, Exert Steward of Solidarity: Create a 1/1 white Warrior creature token with vigilance. (An exerted creature won't untap during your next untap step.)