Is Katara, Seeking Revenge legal in Standard, Modern, and Commander?

Katara, Seeking Revenge is legal in: Legacy, Vintage, Commander, Historic.

Katara, Seeking Revenge

Q: What type of card is Katara, Seeking Revenge?

Katara, Seeking Revenge is a Legendary Creature — Human Warrior Ally. Its oracle text reads: "As an additional cost to cast this spell, you may waterbend {2}. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.) When Katara enters, draw a card, then discard a card unless her additional cost was paid. Katara gets +1/+1 for each Lesson card in your graveyard."

Legendary Creature — Human Warrior Ally

As an additional cost to cast this spell, you may waterbend . (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for .)