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
Complete Rinri's quest
Complete Thorn quest
Hatch the God Egg
Collect all Wickerlings
Complete Willo's quest
Unlock all treasure chests
Complete the story
Become the Postmaster
Defeat Screetch
Get the biggest wallet
Discover Fosfor’s Lair
Deliver the cake to the inventors house
Unlock all the Beelines
Try every ball style
Complete the temple trials
Discover the heart cluster at the bottom of the sea
Collect the Divefish
Save Spina
Toot the noisemaker 1000 times
Customise Yoku’s ball
Defeat the Spider
Ride the Beeline
Befriend a Sootling
Take the surviving egg to Dipperloaf
Suck up a slug with the Slug Vacuum
Find the Post-office
Free Kickback
Toot the noisemaker 100 times
Blow the noisemaker