PoisonBug
Poison and Bug types: weaknesses, resistances and Pokémon
Poison and Bug Pokémon take double damage from Fire, Flying, Psychic and Rock moves and resist Grass, Fighting, Poison, Bug and Fairy moves.
The balance is even: 4 weaknesses and 5 resistances or immunities.
Poison moves are super effective against Grass and Fairy and not very effective against Poison, Ground, Rock and Ghost. Bug moves are super effective against Grass, Psychic and Dark and not very effective against Fire, Fighting, Poison, Flying, Ghost, Steel and Fairy.
To beat these Pokémon, your best pick is Fire, Flying and Psychic moves. Avoid Grass, Fighting, Poison and Bug moves, which deal little or no damage.
There are 12 Pokémon with this combination, such as Weedle, Kakuna, Beedrill and Venonat.