Here is the full list of all 8 Roots of Yggdrasil achievements.
Have 15 or more curse cards into your Deck.
Meet Hoenir
Complete your first loop.
Build the Workshop in the Holt.
Build the Greenhouse in the Holt.
Witness Lif and Thrasir's Feelings Sprout.
Complete a loop with 7 cards or less into your Deck.
Complete a loop with 50 cards or more into your Deck.