Pokemon evolutions by happiness

This is a list of pokemon that evolve after becoming friendly. The majority of these pokemon are baby pokemon that were added as pre-evolutions in later games.

You can increase a pokemon's happiness in many ways. The simplest is walking around with the pokemon in your party, battling and growing them, but not letting them faint. You can also give them a Soothe Bell to hold, which will increase happiness at double the rate. You can also give your pokemon massages at various places and certain berries raise happiness. For more info, see this PokéBase question: What's the easiest way to raise a pokemon's happiness?

This information applies to any games that feature both pokemon from the chain, including Pokemon Black & White.