Here is the full list of all 49 Spirit of the Island achievements.
Fix the abandoned house
Visit Sharp Cliffs island
Visit Boar Mountain island
Meet All NPCs
Talk to the Elder
Get Farming level 5
Get Mining level 5
Get Foraging level 5
Get Cooking level 5
Get Fishing level 5
Get Exploration level 5
Get Combat level 5
Get Social level 5
Get Electronics level 5
Get Crafting level 5
Get all skills to level 5
Collect Each Plant in the Game
Defeat Every Creature
Earn a total of 1 million credits
Visit Grey Rocks island
Visit Wood Alley island
Visit The Island of Six
Visit Blue Shell beach
Visit Sand Cliffs island
Visit Golem Eye island
Visit Forever Ruins island
Visit The Golden Swamp island
Visit Green Valley island
Visit All Islands
Defeat the Pirate Boss
Craft EVERY Item in Game
See All Events
Collect All Types of Insects
Catch All Types of Fish
Plant All Types of Crops
Max Out the Relationship with All NPCs
Buy a Luxury boat
Upgrade your house to level 3
Finish the main Story
Find 50 Treasures
Hire 15 tourists
Collect all treasures in the Museum
Build all the vehicles
Find a map for Alina
Unlock All Achievements
Build Every Building
Find All Caves
Live on Your Island for a Year
Create a Key of Elements