Here is the full list of all 21 Frost achievements worth 1,000 gamerscore.
Finish The Priest scenario
Win a game without any Survivor in your deck
Finish The Tracker scenario
Win on medium difficulty
In medium difficulty, win the game without finding the Refuge
Win a game with one Health Point
Finish The Hunter scenario
Finish The Guide scenario
Finish The Leader scenario
Finish The Meditator scenario
Win a game after having had the Frost counter on 1
Win a game in any mode
Win a game in easy mode
Win a game without any Fatigue card in your deck
Travel 40 times in Endless
Win on hard difficulty
Win a game without any idea in your deck
Finish The Frigomancer scenario
You won on Impossible difficulty :O Congrats!
Finish The Recruiter scenario
Finish The Skeptic scenario