There were not many Electric-type Pokemon introduced in Johto, but the ones that were, are mighty.
Kanto started the Pokemon journey. Electric-types such as Pikachu, Electabuzz, and Zapdos set the standard for the powerful Electric-types that would follow in Johto and future regions.
While a lot of Electric-types in the Johto Dex are also native to Kanto, a few were brand new when Generation II was revealed. They are all pretty iconic and did a good job of continuing the Electric-type legacy.
Top 3 Electric Pokemon from Johto
#3 - Lanturn
Lanturn is a fun Water/Electric-type. It is truly only weak to Grass and Ground-type moves. This Pokemon is pretty bulky with a huge base HP stat of 125. The next best are Special Attack and Special Defense at 76.
Lanturn can do supereffective damage to Rock, Fire, Ground, Flying, and Water. Those types of Pokemon are extremely common. Lanturn certainly has the leg up over other Water-types from Johto with the dual Electric typing.
#2 - Ampharos
Ampharos is known as the Light Pokemon. That has to do with its efforts in keeping lighthouses lit, as shown in the games and anime. Its tail is said to shine so bright that it can even be seen from outer space. That is wild.
As a battler, it is only weak to Ground-types. It also has very good base stats. 90 HP and Special Defense gives it some bulk to take hits in battle. It also has a 115 base Special Attack.
#1 - Raikou
Raikou is definitely the best new Electric-type discovered in the Johto region. The legendary beasts are arguably the best and most popular trio of Legendary Pokemon. Raikou is said to represent the lightning strike that caused the Brass Tower to burn.
Its base stats aren't as high as some other Legendary Pokemon, but it is extremely fast, with 115 Speed, and has 115 Special Attack. The entire lore behind the Legendary beast trio is amazing.