Here is the full list of all 16 LEAVES - there are The Return achievements.
Niche4 puzzle solved
Pfeffersack sleeps at the noses
Used the Travelstone 3 times
Gave Pfeffersack the salad
Solved the hand puzzle
Found 5 inhabitants
Opened the portal
Opened the underground
Solved the electric puzzle
Collected 3 drops
Upset the Treefruities
Found the magnifier
Didn't need any help
Found 10 inhabitants
Found 15 inhabitants
Played the game without interruption