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