Dark-type Pokémon

Pure Dark-types

Immune to Psychic attacks; strong against Dark and Ghost attacks; weak against Bug and Fighting attacks
Umbreon

Dark/Fire-types

Immune to Psychic attacks; strong against Dark, Fire, Ghost, Grass, Ice and Steel attacks; weak against Fighting, Ground, Rock and Water attacks
Houndour
Houndoom

Dark/Flying-types

Immune to Ground and Psychic attacks; strong against Dark, Ghost and Grass attacks; weak against Electric, Ice and Rock attacks
Murkrow

Dark/Ice-types

Immune to Psychic attacks; strong against Dark, Ghost and Ice attacks; weak against Bug, Fighting, Fire, Rock and Steel attacks
Sneasel

Rock/Dark-types

Immune to Psychic attacks; strong against Dark, Fire, Flying, Ghost, Normal and Poison attacks; weak against Bug, Fighting, Grass, Ground, Steel and Water attacks
Tyranitar