Here is the full list of all 39 Mystic Vale achievements.
End a game owning at least 5 Level 3 Advancements
Earn at least 30 Mana from a single Harvest
Obtain an Advancement for free
Use the Mindful Owl's ability 3 times in a single game
Win a Game
Gain 10 or more blue Victory points in one turn
Purchase at least 5 Vale Cards in a single game
Obtain 7 or more grey victory points in one turn
Have 3 Advancements with the Guardian Symbol on the same card
Cancel 2 Decay symbols on the same card with a Lifebringer Seed
Push 5 times in a single Planting phase without Spoiling
Complete all tutorials
Win an Online Game
Win a game without spoiling
Gain enough Growth to cancel out all 9 cursed land cards that you begin with
Draw all 20 cards into your Field without Spoiling
Purchase all 3 Bear Totem Advancements in a single game
Win a game without purchasing any Fertile Soil Advancements
Purchase all Ent Elder Advancements in a single game
Complete a game with more Growth than Decay across your entire deck