Jolteon

As a pure Electric-type, Jolteon faces heavy competition from Raikou due to the latter's better bulk and power, which means that it outclasses Jolteon as a special wall and as a phazer. Furthermore, the popularity of other Electric-types such as Zapdos makes Pokemon like Steelix and once again Raikou popular, which hinders Jolteon even more. However, there's still a reason why Jolteon is viable in OU: Baton Pass. With boosting moves such as Agility and Growth, a sky-high Speed stat, and an Electric STAB attack that allows it to pressure common phazers like Skarmory and Suicune, Jolteon makes for a very effective user of this move.