The drop rate in Acrylia Caverns seems to be quite poor, I cleared the whole zone 3 times and got about 5 or 6. However I can confirm they drop off the Shik'Nar mobs as well
After trying farming several of these camps, I've come to the following conclusions. 1) Deep Cavern Lotuses are by far the best camp. High drop rate, easy to find, good respawn. 2) You can farm Undershore and Corathus Creep for hours and get 0 drops. 3) If you're looking for both Modest and Simple powders, Kedge Keep and Old Sebilis are for you. 4) Getting to the Thought Horrors camp is time consuming. Farming the lesser dudes doesn't yield much. There are better camps. 5) If you want Binding and Simple, Acrylia Caverns are for you. The Inner Sanctum is better for higher level drops. The skellies right before the teleport room are one of the best Modest powder camps I've seen.
The rest I haven't tried. I found the Lotuses, and stopped looking. Period.
So... Like anyone else looking to obtain these things I'm working on my research skill. I had been farming elementary binding powder in Tower of Frozen Shadow and the drop rate was fairly decent. Like 1 powder for every 4 or 5 kills. I collected stacks in no time.
Hoping the drop rate would be similar in a higher lvl zone, just with much stronger mobs I opted to skip over skill-ups using the modest binding powder and just go right to simple binding powder that drops in Old Seb. I guess If I had to do it over again I would have tried to skill up with the modest binding powder as the drop rate has decreased significantly since the days of hunting elementary powders in ToFS. I would have to say the drop rate in Old Seb is maybe 1 out of 10? maybe even less.
Just posting my experience farming these things in the hopes to help others out. If other people are in the zone hunting, definately send a tell asking that if they don't need the powders you will be more than happy to buy them from them.
I think my research skill at the time I write this is around 145 and I may just save the precious simple binding powders that I have on me until I am trivial making modest enchanted spell parchments as well as the modest scrolls of static strike.
The caster grimlings in the inner sanctum of Acrylia Caverns drop these fairly often. Sometimes the ones in the lava room prior to the inner sanctum clickie drop them as well.
This and Binding powder drop off the Frogloks Shammies/Wizzies and Chanters of the Ilis and Krup persuasion in Sebilis and occasionally off the Myconids.
I looted simple binding powder off of the following. The drop rate seemed to be pretty poor, with only 8 dropping. I cleared the entire northwest corner of the zone around the Droga zone-in.
A Goblin Death Caster A Goblin Spirit Chanter A Goblin Flame Dancer A Goblin Spirit Lord
The most consistent place I've found to farm these is Guk LDON's at level 55. This is the dungeon that you would get if your group average level is between 53-57. If your group level is 48-52 request a "Hard" adventure and you will get the same dungeon. I get about 3-5 powders per run. I also tried the "thought horror" camp in The Deep but the drop rate there was quite variable. I have gotten 3 in a single clearing and then also I have went an hour without getting any.
This was also found on a Drumrek Shaman in Goru'kar Mesa. Perhaps a mistake???
Confirmed
Notes: Interestingly enough, at level 63 ive noticed that there is an even spread between greens and light blues, and its only the light blues (at this level) that drop the powders. Will kill a load more and see if this trend holds true.