List of Pokémon with cross-generational evolutions

This is a list of Pokémon that evolve into a Pokémon originating from a different generation. For example, (a Generation II Pokémon) evolves into  (a Generation I Pokémon).

A few of these Pokémon, as a result of new evolutions, become a part of evolutionary families with branched evolutions. Those Pokémon which evolve into a Pokémon of a previous generation, instead of from it, are specifically baby Pokémon.

Trivia

 * Generation IV introduced the most evolutionary relatives to Pokémon from previous generations, with 29, and Generation VI introduced the fewest evolutionary relatives to Pokémon from previous generations, with only one, . The only generations that didn't introduce any new cross-generational evolutions (not counting regional variants) are Generation V and Generation VII.
 * is the only Pokémon to have both a pre-evolution and an evolution ( and, respectively) introduced in the same generation.
 * is the only Pokémon to have an evolution introduced in a later generation that was later able to evolve once again.