The second-generation (Generation II) of the Pokémon franchise features 100 fictional creatures introduced in the 1999 Game Boy Color games Pokémon Gold and Silver.
The following list details the 100 Pokémon of Generation II in order of their National Pokédex—an in-game electronic encyclopedia that provides various information on Pokémon—number. The first Pokémon, Chikorita, is number 152 and the last, Celebi, is number 251. Alternate forms that result in type changes and Mega Evolutions are included for convenience.
Two new types were introduced in Pokémon Gold and Silver – namely the "Dark" and "Steel" types – which were intended to better balance the gameplay of Pokémon battles. Dark and Steel types fare well against "Psychic" attacks, which was a dominant type in Red and Blue. The concept of breeding was introduced in the second generation of Pokémon games as well, which allows players to manipulate the skills of their Pokémon to a greater degree. Some of the new Pokémon introduced in Gold and Silver are pre-evolutions of other Pokémon, such as Pichu and Igglybuff. These baby Pokémon are only available by breeding their adult versions.