From Bulbapedia, the community-driven Pokémon encyclopedia.
Iron Fist (Japanese: てつのこぶし Iron Fist) is an ability introduced in Generation IV that causes punching attacks to increase in power by 20%.
Punching attacks are:
One Pokémon has this ability.
Pokémon with Iron Fist
No Pokémon have Iron Fist as their only ability.