Here is the full list of all 25 Earthlock: Festival of Magic achievements worth 1,000 gamerscore.
Arrived at Plumpet Island
Gnart joined the Party
Defeated the Temple Guardian
Helped Ive after she crashed the plane
Rescued Taika from the Bandit
Olia rejoined the party
Found PAT in the Warehouse
Received the Lys Aegis Talent from Lady Lumia
Rescued Benjo from the Karba Prison
Arrived at the Memory Chamber
Completed the game
Defeated one of every enemy
Opened 50 chests
Harvested 1000 fruits
Levelled every type of plant to level 3
Grew a plant in every garden slot
Crafted one of every Perk Talent
Levelled all characters to level 20
Levelled up all Bonds to level 5
Equipped a Talent in every available slot
Released all the barnacles to play on Plumpet Beach
Released 50 tormented Ghosts
Gained Gold Rank on all Tournaments
Defeated the Mushriga
Defeated the Hollow Knight