I guess in a way Frost Dragon Bones over normal Dragon Bones, it's 3x(?) faster but costs alot more money. Wouldn't be too bad if it had for instance a level requirement in prayer to bury, but essentially you can get 1m exp per hr with FDBs at level 1 prayer. Overall though, I do agree that most methods are pretty nicely tiered. Ah Dragon bones have dropped quite a lot. Still ,between those and frosts you have Dagannoth & Ourg bones which slot in between the 2 as alternatives. Ah true, didn't think of those, even if it's pretty unrealistic for at least say Ourg, they still are there. I think you've forgotten there is a difference between Ourg bones from zogres and Ourg bones from Graar. The bones from Graar are reasonably priced and buy easily.