The Apocalypse Add-on for Stellaris (Windows) has 5 achievements worth 200 gamerscore.
Seal a world of Fanatic Purifiers, Ravenous Swarms, Determined Exterminators with a Global Pacifier
Use a World Cracker to destroy another Empire's capital planet
Defeat a Fallen Empire's Titan fleet with a Titan of your own
Kill the Great Khan in battle
Destroy another Empire's Colossus while it is in the process of firing on a planet