Here is the full list of all 20 The Frostrune achievements.
Sleipnr was the fastest horse of them all
Well, hello sir!
When Ragnarok is over, the survivors will gather at Iðavöllr
It is better to never ask for help, than to ask one time to many
Baby, it’s time to dance!
The wisest squirrel in the tree
When friends are together they are the strongest
Thou shalt pass all doors
Menglöðs beauty would melt all ice
You don’t know until you try
Happy is she who plays with fire
You are no friend of beavers!!
This is no place for the living
The wisest thing to do is to make a friend
The world is big when you can see it all
No secret was hidden from Heid
Andrimner is he who makes food in Valhall
The dwarf is the master of rock
Hymir gives the greatest catch
Welcome to Ullrs realm