The Johto Region -- or Generation 2 as some like to call it -- had quite a bit to live up to after the first Pokémon games. Following the popularity of Gen 1, Game Freak tried to make lightning strike with this second group of Pokémon, and in many ways they did. The games became more balanced and there were 100 new Pokémon added to the roster, most of which are still fan favorites to this day.
However, with that many Pokémon being added, quite a few fell by the wayside, not even receiving a Mega Evolution or an Alolan Form. This doesn’t mean they’re bad Pokémon, but like the Kanto and Hoenn lists, this is just to give some appreciation to Pokémon who are just less loved.
Image Source: Here