Which "Untouched" Gen 2 Pokémon are Still the Most Useful?

Pokémon has a pretty consistent habit of going back to their old work and shaking things up with evolutions, new forms, or gimmicks like Megas, or Z-Moves. However there are still some holdouts that are the same old Pokémon we've known since they were first introduced, so let's see which Johto Pokémon that have remained unchanged are still great options that can stand up to all the favorites!