Is Ahn-Crop Champion legal in Standard, Modern, and Commander?

Ahn-Crop Champion is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Ahn-Crop Champion

Q: What type of card is Ahn-Crop Champion?

Ahn-Crop Champion is a Creature — Human Warrior. Its oracle text reads: "You may exert this creature as it attacks. When you do, untap all other creatures you control. (An exerted creature won't untap during your next untap step.)"

Creature — Human Warrior

$0.08 ↗20 similarCommander, Modern

You may exert this creature as it attacks. When you do, untap all other creatures you control. (An exerted creature won't untap during your next untap step.)

Set Amonkhet

Rarity Uncommon

Mana Value 4

Artist Craig J Spearing

Collector # 194