Is Heart Wolf legal in Standard, Modern, and Commander?

Heart Wolf is legal in: Legacy, Vintage, Commander.

Heart Wolf

Q: What type of card is Heart Wolf?

Heart Wolf is a Creature — Wolf. Its oracle text reads: "First strike{T}: Target Dwarf creature gets +2/+0 and gains first strike until end of turn. When that creature leaves the battlefield this turn, sacrifice Heart Wolf. Activate only during combat."

Creature — Wolf

First strike<br>: Target Dwarf creature gets +2/+0 and gains first strike until end of turn. When that creature leaves the battlefield this turn, sacrifice Heart Wolf. Activate only during combat.