Generation Iv
Ice Body
The Pokémon regains HP in a hailstorm.
Detailed Effect
This Pokémon heals for 1/16 of its maximum HP after each turn during hail, and it does not take hail damage regardless of type.
Pokémon With Ice Body
21 canonical Pokémon forms can have this Ability.

Snorunt
Glalie
Spheal 
Sealeo
Walrein
Vanillite
Vanillish
Vanilluxe
Bergmite
Avalugg
Arctovish
Hisuian Avalugg
Seel
Dewgong
Regice
Glaceon
Mr Rime
Frigibax
Arctibax
Baxcalibur
Galarian Mr Mime