Generation Iv
Leaf Guard
Prevents status problems in sunny weather.
Detailed Effect
This Pokémon cannot be given a major status ailment during strong sunlight. This ability does not heal prior status ailments. Rest will fail altogether with this ability in effect. Yawn will immediately fail if used on this Pokémon during strong sunlight, and an already-used Yawn will fail if the weather turns to strong sunlight in the meantime.
Pokémon With Leaf Guard
23 canonical Pokémon forms can have this Ability.

Tangela
Hoppip
Skiploom
Jumpluff
Tangrowth
Leafeon
Swadloon
Fomantis
Lurantis
Bounsweet
Steenee
Tsareena
Zarude
Lurantis Totem
Zarude Dada
Chikorita
Bayleef
Meganium
Roselia
Budew
Petilil
Lilligant
Hisuian Lilligant 