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