The bags from humanoids.. It won't be fast cause they are filled with all kinds of mats but if you get in a event and aoe the swarms you get to loot anything that drops. So it can be faster than one by one killing..
---------- Post added 2012-08-31 at 10:52 PM ----------
Also kessex doesn't drop much of the second tier mats for leather working and such, the next area does though..