Electric, fire, steel, rock and poison.
The weakness of electric type Pokemon is ground type Pokemon.
Ground
Ground
Ground
The only weakness there is a Ground-type Pokémon.
Use Ground-Type Pokemon cause Electric-Type moves DOES NOT effect Ground-Type Pokemon!
Psychich and Ground.
Poison type Pokemon are weak to psychic and ground type moves.
all you need is a ground type, but for octillery, maybe use an electric Pokemon or grass one, or it will slaughter your ground one otherwise
Ground-type Pokemon are weak against Water, Grass, and Ice-type attacks.
The Electric-type's only weakness is Ground. Electric moves are ineffective on Ground and resisted by itself and Flying.
Psychic Pokemon are weak to Dark Type attacks