Here is the full list of all 25 Earthlock: Festival of Magic achievements worth 1,000 gamerscore.
Return all barnacles to Plumpet Island
Complete all Tournaments with Gold Ranking
Fully level up all Bonds between all characters
Open 50 chests
Defeat the Mushriga
Help 50 ghosts to rest at peace
Find Pat in the warehouse
Olia rejoins the party
Rescue Taika from the Bandit
Harvest 1000 fruits
Help Ive from the crashed plane
Arrived at Plumpet Island
Gnart joined the Party
Defeated the Temple Guardian
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
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
Equipped a Talent in every available slot
Defeated the Hollow Knight