Here is the full list of all 16 Wildfrost achievements.
Defeat the Frost Guardian with a Scrappy Sword
Stack 50 Shell on a single target
Stack 5 Block on a single target
Deal 100 damage in a single hit
Feed the Muncher a Consume item
Spare the Naked Gnome
Defeat the Heart of the Storm
Stack 20 Shroom on a single target
Win a Daily Voyage
Achieve a 3 Win Streak
Stack 15 Snow on a single target
Buy 3 Charms from a single shop
Sacrifice 10 allies in a single battle
Deal 50 damage in a single hit
Survive an attack from King Moko and win the battle
Win a battle with just your Leader remaining