GroundPsychic
Ground and Psychic types: weaknesses, resistances and Pokémon
Ground and Psychic Pokémon take double damage from Water, Grass, Ice, Bug, Ghost and Dark moves, resist Fighting, Poison, Psychic and Rock moves and are immune to Electric moves.
The balance is even: 6 weaknesses and 5 resistances or immunities.
Ground moves are super effective against Fire, Electric, Poison, Rock and Steel and not very effective against Grass and Bug. Psychic moves are super effective against Fighting and Poison and not very effective against Psychic and Steel.
To beat these Pokémon, your best pick is Water, Grass and Ice moves. Avoid Fighting, Poison, Psychic and Rock moves, which deal little or no damage.
There are 2 Pokémon with this combination, such as Baltoy and Claydol.