Is Guildpact Greenwalker legal in Standard, Modern, and Commander?

Guildpact Greenwalker is legal in: Historic.

Guildpact Greenwalker

Q: What type of card is Guildpact Greenwalker?

Guildpact Greenwalker is a Creature — Plant Rhino. Its oracle text reads: "When Guildpact Greenwalker enters, you may choose a creature card in your hand. If you do, that card perpetually incorporates {1}{G} and gets +4/+4. Multicolored creatures you control have ward {2}. Power/Toughness: 4/4"