The The Fate of Atlantis - Episode 1: Fields of Elysium Add-on for Assassin's Creed Odyssey has 5 achievements worth 110 gamerscore.
Win the conquest of Elysium with freed humans from the 3 main regions.
Destroy all of the Marble Maiden Tributes.
Remember who you are.
Kill all Overseers in Elysium.
Collect all the Keeper's Insights in Episode 1.