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