The Nemesis Add-on for Stellaris has 10 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
Complete a mutually friendly First Contact with an empire with no negative incidents
Vivisect an alien
Start a full fledged first contact war before communications have been fully established
Disavow all knowledge of an Asset during an Operation
Have an Intel Level of 100 on five different empires simultaneously
Complete at least ten distinct operations during a game