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