Version-exclusive Pokémon in Let's Go Pikachu & Let's Go Eevee
Like all the paired games in the Pokémon series, Let's Go Pikachu & Let's Go Eevee each include Pokémon that cannot be obtained in the alternate version. To obtain Pokémon missing from your version you need to trade with someone who has the opposite version.
The version exclusives are the same Pokémon as those in the original Pokémon Red & Pokémon Blue, but they are spread differently.