The Alien Hunters Add-on for XCOM 2 has 10 achievements worth 195 gamerscore.
Use all ruler armor abilities in a single mission
Purchase all of the final tier hunter weapons
Kill the Archon Ruler
Kill all three alien rulers in a single game
Kill the Berserker Ruler
Kill the Viper Ruler
Investigate the Abandoned Research Facility
Kill an alien ruler the first time you encounter it
Use a ruler armor ability against an alien ruler
Kill an alien ruler while it attempts to escape