We got this from Elf Online!

Every game has secrets, the same as Elf Online.  Some players claim that the most elusive thing in Elf Online is the combination of different pets and different skill stones. To raise the best pet equipped with the most suitable skill stone, players have to collect hundreds of top skill stones and test in order to get a satisfying result.  

This sounds impossible in the past, but don’t worry, we have gotten a secret report with the location of the skill stones now.

Check out the drop info, and the stone locations!

Tranquil Seacoast 1: Edge Storm 1 and Life Lick Up 1  
Tranquil Seacoast 2: Relive 1 and Disability 1  
Phantom City: Recovery 1

Samsara City: Edge Storm 1 and Burning Storm 1 (from the boss in Samsara City) 
Evil Hole: Edge Storm 3, Recovery 2 and Edge Tornado 
Cavern of Forgetness: First Aid 1  
Eight Diagrams: Recovery 1,  Filch 1, Relive 1, First Aid 1, Edge Storm 1 
Endless Plain 1: Filch 2 and Burning Storm 1 
Endless Plain 2: First Aid 1 
Endless Plain 3: Diligency Bless 2, Life Lick Up 2, Burning Storm 3 and First Aid 2 
Secret Hole of Treasure Floor 1: Recovery 2  
Secret Hole of Treasure Floor 2: Blizzard 3 and Landification 2

Mine of Confusion: Poison

Delusion Forest 2: Bloody 1 and Frost Spine 4  
Delusion Forest 3: Life Lick Up 3, Choke 4 and Poison 5   

Painstaking Desert 1: Recovery 2 and Landification 2 
Painstaking Desert 2: Poison 5, Swoop 2, Bloody 1, Frost Spine 4, Curse 1 
Megalith City: Premeditation 1 

Furthermore, Elf Online (http://elf.happymmo.com/) has worked out the list of both common and rare items dropped from monsters and bosses. Please click the link below for more information:

Normal Monster Drop: http://elf.happymmo.com/elf-online-54.html

Boss Drop: http://elf.happymmo.com/elf-online-56-176.html