BL Chests, Dyes, Minis and other things like memories box.the most evil are the BLChest, i bought all my keys (and sometimes got it from drop, storyline and few free ones from ANet), and i have NEVER got anything good from those chests. if u r after wild magic backpack/glider, u need luck and/or a lot of money, if u r lucky 1 BL key is all u need, if u r unlucky u might need 170+ keys.