Here is the full list of all 47 Fossil Hunters achievements.
Collect all other achievements
Complete all the Collector's requests
Finish the game
Die in a pit 100 times
Make 100 skeletons
Collect all Abyss journal entries
Collect all journal entries
Pick up an idol from the treasure hoard
Unlock all schematic doors
Drop a golden idol in a pit
Collect all golden idols
Use 20 supports
Drop 50 fossils in pits
Build 5 colossal skeletons
Pick up the Sammy rock and bring it to the elevator
Have all three power-ups active at once
Transport 12 or more items with the elevator
Submit 50 clean & pristine skeletons
Make 50 skeletons
Submit a skeleton with every piece damaged
Collect all Magma Chamber journal entries
Build 10 huge skeletons
Unlock the dynamite shopkeep
Use 20 bridges
Unlock the bridge shopkeep
Get all destruction achievements
Have a fossil smashed by a lavamander
Collect all Mushroom Caverns journal entries
Build 15 big skeletons
Unlock the support shopkeep
Use 20 lamps
Prevent a death with a dodge roll
Have a fossil covered in moss
Collect all Digsite journal entries
Use 20 dynamite barrels
Unlock the lamp shopkeep
Collect a golden idol
Have a fossil eaten by a crawler
Play as each of the Fossil Hunters
Have your multiplayer friends drop out
Rearrange the furniture in the lab
Make 10 skeletons
Leap the maximum distance
Unlock a schematic door
Have a fossil smashed by a cave-in
Make a skeleton
Bring 20 new objects into the lab