Is Karn, Legacy Reforged legal in Standard, Modern, and Commander?

Karn, Legacy Reforged is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Karn, Legacy Reforged

Q: What type of card is Karn, Legacy Reforged?

Karn, Legacy Reforged is a Legendary Artifact Creature — Golem. Its oracle text reads: "Karn's power and toughness are each equal to the greatest mana value among artifacts you control. At the beginning of your upkeep, add {C} for each artifact you control. This mana can't be spent to cast nonartifact spells. Until end of turn, you don't lose this mana as steps and phases end."

Legendary Artifact Creature — Golem

$12.2420 similarCommander, Modern

Karn's power and toughness are each equal to the greatest mana value among artifacts you control.

At the beginning of your upkeep, add for each artifact you control. This mana can't be spent to cast nonartifact spells. Until end of turn, you don't lose this mana as steps and phases end.