Nightmares can also be hunted for barbed hides.
They are quite a bit easier to kill than dragons.

In Felucca nightmares give 20 hides each, which is easy farming if you don't mind dodging the occasional PK from time to time.

For me the easiest place to kill drakes is fire temple, just lure them out a few at a time, whack them and head back in.
Not sure if greater dragons spawn there now though...