Generation V
Poison Touch
May poison targets when a Pokémon makes contact.
Detailed Effect
This Pokémon's contact moves have a 30% chance of poisoning the target with each hit. This counts as an extra effect for the purposes of Shield Dust. This ability takes effect before Mummy.
Pokémon With Poison Touch
11 canonical Pokémon forms can have this Ability.

Seismitoad 

Skrelp
Dragalge
Grafaiai
Alolan Grimer
Alolan Muk
Grimer
Muk
Croagunk 
Toxicroak
Sneasler