In Let’s Go Pikachu and Let’s Go Eevee, a small number of rare Pokemon can be obtained completely for free! Sometimes a small challenge must be completed, but much of the time all you need to do is talk to a Trainer.
It’s best to save your game before receiving the Pokemon since their natures are randomly assigned. However, their individual values or determined values are nearly maxed out compared with wild Pokemon. Many of these Pokemon can also be found in the wild, but they’re often harder to find and capture.
Magikarp
A Magikarp can be purchased from a man in the Pokemon Center on Route 4 for P 500. Most people will say this is a rip-off, but like the other gift Pokemon this level 5 Magikarp has nearly maxed out stats. However, it’s nature will be random. Save before buying!
Bulbasaur
A Bulbasaur can be obtained from a woman who looks after sick and injured Pokemon in Cerulean City. This woman’s house is directly west of the Pokemon Center. If you’ve captured enough Pokemon, she’ll give you this Level 12, Grass/Poison-type Pokemon.
Charmander
A Charmander can be obtained from a man who is tired of training Pokemon. He is located on a small hill at the northwest corner of Route 24, which is just north of Cerulean City. This Trainer will give you the Level 14 Fire-type Pokemon just for talking with him.
Squirtle
A Squirtle can be obtained from Officer Jenny who has chased this troublesome Squirtle from Cerulean City. If you’ve captured enough Pokemon, she’ll give you this Level 16 Water-type Pokemon.
Arcanine or Persian
In Vermilion City a man will be sitting on a bench just north of the Pokemon Gym. Speak with him to begin a short quest: he’ll ask you to catch five Pokemon depending on the version you’re playing. If you’re playing Let’s Go Pikachu, you must capture five Growlithe to receive a Lv 16 Persian. If you’re playing Let’s Go Eevee, you must capture five Meowth to receive a Lv 16 Arcanine.
Hitmonlee and Hitmonchan
In Saffron City, defeat the Karate King in the Fighting Dojo to get the option between a Hitmonlee or Hitmonchan. Only one can be chosen, but another can be captured at Victory Road.
Lapras
A businessman within Silph Co (Saffron City) will give you a Lv 34 Lapras just for speaking with him. This man is sitting in a small resting area on the 7th floor.
Porygon
After rescuing Silph Co in Saffron City, speak with the man in front of the Pokemon Center to receive a Lv 34 Porygon.
Omanyte and Kabuto
Omanyte and Kabuto are another set of rare Pokemon that you must choose from. While in Mt. Moon you’ll come across two fossils just before the exit. You will only be able to choose one, so choose wisely. Take this fossil to the Pokemon Lab on Cinnabar Island to revive it into one of these ancient fossil Pokemon. The Helix Fossil revives an Omanyte, and the Dome Fossil revives a Kabuto. Both can then evolve once they reach the appropriate level. Kabutops (the evolved form) specializes in attack while Omastar specializes in special attack.
Although only one fossil can be chosen from at Mt. Moon, another can be found on the second floor of the Cerulean Cave. After becoming the Pokemon League champion, enter the cave and investigate the florescent rock in the middle of the second floor to discover a random Helix Fossil, Dome Fossil, or Old Amber.
Aerodactyl
Aerodactyl is another ancient and extinct Pokemon that can be revived from a fossil. The item you need is ancient Pokemon DNA held by a mosquito that has been trapped in tree sap, which then fossilized over millions of years: Old Amber. Grab the Old Amber at the Pokemon Museum in Pewter City. You’ll first need to teach your Partner Pokemon the secret technique Chop Down from the S.S. Anne, then you can cut the bush on the east side of the Museum. Take the Old Amber to the Pokemon Lab on Cinnabar Island to revive it.
After becoming the Pokemon League champion, enter the cave and investigate the florescent rock in the middle of the second floor to discover a random Helix Fossil, Dome Fossil, or Old Amber.