the best Pokemon to use against electric Pokemon is ground/rock Pokemon.
the best pokemon to use is mudkip.
Water Pokemon. You can also use rock Pokemon such as geodude or onix. Do not use grass or steel Pokemon these types are week against fire.
Its good to use whatever Pokemon you bond with best. But I suggest you use a Rock type Pokemon, or a fire type. You can catch a Darkaruma (spelling?) in the Desert Resort, which works well against Burgh's Leavanny.
Koga uses primarily Poison-type Pokemon. Psychic Pokemon would be the best bet. Ground-type Pokemon would also work, but will not be as effective against his Venomoth or Crobat.
the best Pokemon to use against electric Pokemon is ground/rock Pokemon.
if you have Groudon and it has fissure use him..
it would be best to use ghost Pokemon against the gym leader
The best Pokemon to use against Crasher Wake is any Electric type. It's recommended to have a Grass type as backup and to help deal with his Quagsire who is four times weak against Grass.
I would use Bastiodon and spam Rockslide or Ancient Power
Ground works best against electiricity do you should use Pokemon like onix, geodude and so on to beat them
water,fire and grass
lapras, dragonite, nidoking,zapdos,and mew
grass and electric types
the best pokemon to use is mudkip.
Morty has ghost-type Pokemon, it's best to use a Pokemon that know's a dark type attack. Ghost Pokemon do not have many weaknesses but dark is strongest against them.
The fifth gym leader is Fantina and she uses Ghost Pokemon. No element is strong against ghost except ghost, so just use your strongest Pokemon. But be careful - ghost to ghost is super powerful, but unless your ghost Pokemon is a much higher level than hers, do not use it since her attacks will be super effective against you. The best Pokemon to have are just a well-rounded team with most of the elements covered.