Here is the full list of all 31 Yoku's Island Express achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Collect every ability upgrade
Activate all Scarabs
Unlock all treasure chests
Complete Thorn quest
Try every ball style
Complete Rinri's quest
Hatch the God Egg
Complete the story
Collect all Wickerlings
Complete Willo's quest
Become the Postmaster
Take the surviving egg to Dipperloaf
Get the biggest wallet
Defeat the Spider
Unlock all the Beelines
Discover Fosfor’s Lair
Befriend a Sootling
Defeat Screetch
Complete the temple trials
Discover the heart cluster at the bottom of the sea
Deliver the cake to the inventors house
Customise Yoku’s ball
Toot the noisemaker 1000 times
Collect the Divefish
Save Spina
Ride the Beeline
Suck up a slug with the Slug Vacuum
Find the Post-office
Free Kickback
Toot the noisemaker 100 times
Blow the noisemaker