Is Aphelia, Viper Whisperer legal in Standard, Modern, and Commander?

Aphelia, Viper Whisperer is legal in: Legacy, Vintage, Commander, Historic.

What type of card is Aphelia, Viper Whisperer?

Aphelia, Viper Whisperer is a Legendary Creature — Gorgon Assassin. Its oracle text reads: "Deathtouch Whenever Aphelia attacks, you may pay {1}{B/G}. If you do, create a 1/1 black Snake creature token with deathtouch. {4}{B}: Until end of turn, whenever one or more Gorgons and/or Snakes you control deal combat damage to a player, that player loses half their life, rounded up. Power/Toughness: 1/3"

Aphelia, Viper Whisperer

Legendary Creature — Gorgon Assassin

Deathtouch

Whenever Aphelia attacks, you may pay . If you do, create a 1/1 black Snake creature token with deathtouch.

: Until end of turn, whenever one or more Gorgons and/or Snakes you control deal combat damage to a player, that player loses half their life, rounded up.