Baby Pokémon are basic Pokémon that are small, cannot breed and are pre-evolutions that were introduced in a generation later than the evolutions before them. However, Togepi and Riolu are the only exceptions, as both and their evolutions are Pokémon belonging to the same generation.
Baby Pokémon are mostly discovered through eggs. Certain species can be produced when the evolution holds a certain type of incense. Occasionally l, they can be found in the wild, such as a munchlax from Gen 4