Besides Normal and Electric, every Pokémon type has more than one weakness. A combination of resistances and immunities can sometimes cancel out these weaknesses in dual-type species, however, leading to a select few dual-type Pokémon with only one weakness.
There is currently only one Pokémon family with no weakness, due to a mixture of type and ability; the Electric-type Eelektross family has the Levitate ability, canceling out Electric's lone Ground-type weakness. Every other Pokémon in the series has at least one weak spot, and even Eelektross can be damaged by super-effective Ground attacks with the help of certain moves or abilities.
A Pokémon's weaknesses don't totally define its usefulness on the battlefield, though. High stats, a great ability, or a wide selection of moves can overcome a Pokémon's other issues. This means the dual-type Pokémon with only one weakness aren't automatically game-breaking or overpowered, as there are many factors to take into consideration when creating a viable Pokémon team. Still, many of these dual types are indeed solid choices.
Poison/Dark-Type Pokémon Are Only Weak To Ground
Poison/Dark-type Pokémon are only weak to Ground-type moves. On top of that, they take half damage from Dark, Grass, Ghost, and Poison-type moves and are totally immune to Psychic-type moves. When Pokémon Legends: Arceus was released, it added two more Poison/Dark Pokémon, in the form of Hisuian Qwilfish, and its new evolution, Overqwil. These new Hisuian Pokémon also share the Ground-type weakness of the others in their group. There are only four evolutionary lines with this type combination so far, consisting of seven total Pokémon:
- Alolan Grimer
- Alolan Muk
- Hisuian Qwilfish
- Overqwil
- Stunky
- Skuntank
- Drapion
Water/Ground-Type Pokémon Are Only Weak To Grass
Water/Ground-type Pokémon are only weak to Grass-type moves, but since both Water and Ground are weak to Grass, they take a boosted 4x damage. They take half damage from Poison, Rock, Steel, and Fire-type moves and are immune to Electric-type moves. There are five evolutionary lines with this combo, totaling nine Pokémon:
- Wooper
- Quagsire
- Marshtomp
- Swampert (and Mega Swampert)
- Barboach
- Whiscash
- Gastrodon
- Palpitoad
- Seismitoad
Bug/Steel-Type Pokémon Are Only Weak To Fire
Bug/Steel-type Pokémon have a 4x weakness to Fire-type moves, but that's their only weakness. They also take half damage from Normal, Bug, Steel, Psychic, Ice, Dragon, and Fairy, and they take only quarter damage from Grass-type moves and are immune to Poison-type moves. There are only six total Pokémon with this type combination so far:
- Forretress
- Scizor (and Mega Scizor)
- Wormadam (Trash Cloak form)
- Escavalier
- Durant
- Genesect
Ghost/Dark-Type Pokémon Are Only Weak To Fairy
Ghost/Dark-type Pokémon once had no weaknesses at all. This changed in Pokémon X and Y, which added Fairy-type Pokémon to the series, giving Ghost/Dark types their only weakness. They take half damage from Poison and are immune to Normal, Fighting, and Psychic-type moves. There are only two only Pokémon with this type combination:
- Sableye (and Mega Sableye)
- Spiritomb
Normal/Ghost-Type Pokémon Are Only Weak To Dark
Pokémon Legends: Arceus introduced the first Normal/Ghost-type Pokémon to the series, with Hisuian Zorua and Hisuian Zoruark making their debut. these Pokémon are only weak to Dark-type moves, which is a pretty good trade-off, as they are immune to Normal, Fighting, and Ghost-type moves, as well as taking half damage from Poison and Bug-type moves.
- Hisuian Zorua
- Hisuian Zoruark