Is Spiritmonger legal in Standard, Modern, and Commander?

Spiritmonger is legal in: Legacy, Vintage, Commander.

What type of card is Spiritmonger?

Spiritmonger is a Creature — Beast. Its oracle text reads: "Whenever this creature deals damage to a creature, put a +1/+1 counter on this creature. {B}: Regenerate this creature. {G}: This creature becomes the color of your choice until end of turn. Power/Toughness: 6/6"