DarkFairy
Dark and Fairy types: weaknesses, resistances and Pokémon
Dark and Fairy Pokémon take double damage from Poison, Steel and Fairy moves, resist Dark and Ghost moves and are immune to Psychic and Dragon moves.
The balance is even: 3 weaknesses and 4 resistances or immunities.
Dark moves are super effective against Psychic and Ghost and not very effective against Fighting, Dark and Fairy. Fairy moves are super effective against Fighting, Dragon and Dark and not very effective against Fire, Poison and Steel.
To beat these Pokémon, your best pick is Poison, Steel and Fairy moves. Avoid Dark, Ghost, Psychic and Dragon moves, which deal little or no damage.
There are 3 Pokémon with this combination, such as Impidimp, Morgrem and Grimmsnarl.