The Leviathans Add-on for Stellaris has 12 achievements.
Recruit a scientist from the Curators
Support the Artisan Troupe for 10 years
Hatch the egg
Birth a new universe
Defeat a horrifying invader
Restore an ancient warship
Take a trophy from a stellar being
Destroy a wraith
Uncover the secrets of an ancient fortress
Purchase a rare resource from the Traders
Destroy an enclave
Lead the non-aligned powers to victory against an awakened empire