List of Pokémon by base friendship

Friendship is a mechanic introduced in Gen I of Pokémon and is consisted of a single-byte integer that ranges between 0 and 255. Friendship can be increased by walking 128 steps, using the Soothe Bell or using specific Poké Balls, while fainting or using bitter medicine decrease a Pokémon's Friendship. Friendship affects the power of the moves Return and Frustration, as well as determining some evolutions.

The Groomer in Greenpine City can increase one of your Pokémon's Friendship once a day.

Pokémon who evolve via Friendship
The following Pokémon evolve through reaching a certain level of Friendship, presumably 220.

List of Pokémon by base Friendship
Most Pokémon have 70 Friendship after being caught, while being hatched out of an egg gives them 120 Friendship to start out with. There are Pokémon however that have lower or higher base Friendship.