Here is the full list of all 22 United Penguin Kingdom: Huddle up achievements.
Make a call for your first huddle-up!
Complete a year in the penguin kingdom
Build a Village Hall
Build a Temple
Build a Vase
Build an Ice Rink
Build a Food Stand
Build a School
Build a Fishing Dock
Build a Carousel
Build a Basic Cooler
Build a Herbs Collector
Build a Newcomer Ramp
Build an Ocean Garbage Collector
Reach a population of 15 penguins
Build a Snow Block Maker
Build a Science Hub
Build a Trawling Dock
Complete the first tutorial
Complete the second tutorial
Complete the third tutorial
Request help from the king