Here is the full list of all 25 EARTHLOCK: Festival of Magic achievements.
Olia rejoins the party
Help 50 ghosts to rest at peace
Defeat the Mushriga
Rescue Taika from the goblin
Harvest 1000 fruits
Help Ive from the crashed plane
Get to Plumpet Island
Gnart joins the party
Defeat the Temple Guardian
Find Pat in the warehouse
Lady Lumia crafts the Lys Aegis Talent
Rescue Benjo
Get to the memory chamber
Complete the game
Defeat one of every enemy
Open 50 chests
Fully level up every type of plant
Fill up the garden with plants
Craft one of each Perk Talents
Level up all characters to level 20
Fully level up all Bonds between all characters
Completely fill all the Talent Boards
Return all barnacles to Plumpet Island
Complete all Tournaments with Gold Ranking
Defeat the Hollow Knight