The Nemesis Add-on for Stellaris has 7 achievements.
Destroy the Galaxy
Become the Galactic Emperor
Lead a rebellion that successfully deposes the Galactic Emperor
As Galactic Custodian, defeat the end-game Crisis and then end the title rather than finishing your term
Start a full fledged first contact war before communications have been fully established
Disavow all knowledge of an Asset during an Operation
Complete at least ten distinct operations during a game