I have many, many favourites which I hardly can decide from, but my vote goes to Eelektross. This Electric-type paired with its fantastic Levitate ability enables it to be completely free of any weaknesses. It can function both as a powerful physical or a special attacker thanks to its similar attack and special attack stats, and has the perfect moves to go with whichever one chooses - Thunderbolt with Acid Spray or Wild Charge with Coil. It also learns Flamethrower. Imagine an Electric-type that learns Flamethrower! It's really rare, that's for sure. That's as good as it can get already. Even with tough competition to face, Eelektross can surely put out a good fight.