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