The YapYap THE DESTROYER Leader Add-on for Halo Wars 2 has 3 achievements worth 30 gamerscore.
Win 3 matches as Yapyap (Multiplayer, Skirmish or Blitz)
Activate the Grunt Goblin charge 10 times. (Multiplayer, Skirmish or Blitz)
Fire 15 methane shells from the Methane Wagon. (Multiplayer, Skirmish or Blitz)