Some great Pokemon with lighting rod are
Mega Sceptile: lighting rod increases Mega Sceptile's high special attack to even higher levels which can allow for a sweep due to it's high speed.
Manetric: lighting rod not only provides a electric immunity but also increases manetric's special attack due to its high speed in additon if you use Mega Manetric you can switch it in on a predicted electric type attack while still regular manetric and gain the special attack increase and then Mega Evolve.
Seaking: due to lightning rod one of two of seaking's weaknesses is removed.
Raichu: high speed and lighting rod increases it's damage potential and due to it having access to fake out it makes a great lead especially in doubles.
Volt Absorb users
Jolteon: very high speed and outspeeds most Pokemon. Hits hard with it's electric type attacks.
Thundurus T: very high special attack and due to volt absorb one of the types that do neutal damage is removed and it's also a flying type giving it immunity to 2 types- Ground and electric.