As with most Pokémon games, fossils make an appearance in Pokémon: Let’s Go, Pikachu! and Let’s Go, Eevee!
There are three in total, but only two can be picked up in the game at one time.
The Dome and Helix Fossils are given to you at the end of Mt. Moon. You can only choose one, however. The Dome Fossil will get you Kabuto later on in the game, while the Helix Fossil will turn into Omanyte.
There’s no wrong option and you can choose either. It all just comes down to personal preference. You will also only be able to get the other fossil Pokémon by trading with other players.
As for the Old Amber, you can get this at Pewter City in the Museum of Science. You’ll need to know the Secret Technique “Chop Down” to get into the back room of the museum where a person will give you the Old Amber.
Now that you have your fossil and Old Amber, it’s time to resurrect these Pokémon. You can do this by completing the following steps:
- Head to Cinnabar Island.
- Enter Cinnabar Lab (the building left of the Pokémon Center).
- Go to the back right corner and talk to the man in the lab coat. He will offer to resurrect any fossil that you have.
- Moments later, you will get that Pokémon.