I was curious what is the rarest Pokémon in the Lets Go series. I would be great if someone could answer this for me. When I say this, I mean by rate of appearance.
I'm going to say Melmetal, because Meltan only evolves into Melmetal in Pokémon GO with 400 Meltan Candies.
But if you are talking about spawn percentages, Dragonair (01% Spawn Rate) and Kangaskhan (01% Spawn Rate) are the rarest.