I know that this question has been asked before here. But I do not recall ever seeing an answer. Has anyone here taken or passed the FAA Part 107 test for commercial use of UAV's? Has anyone found a good online prep resourse that they can recommend?

I have, but I only had to do the online test since I am a Part 61 pilot and I also already have an exemption.
There's 3 links here that will give you a lot of info.
https://www.faa.gov/training_tes ... uag_sample_exam.pdf

Tests aren't available for non-pilots (people who are not part 61) until August 29th.  
faasafety.org has a course that will give you an idea of what to expect.

dak162 Posted at 2016-8-16 06:06
Tests aren't available for non-pilots (people who are not part 61) until August 29th.  
faasafety.or ...

Thanks dak162. I did not know that I will not be eligible for another couple of weeks. Thanks for the link but I think you meant .gov. I just did their tutorial and practice test. It helped a lot. Thanks again.

I'll tell you the Dauntless sUAS drone prep app is actually good prep...it runs through probably more than you may need and will hit you with 225 questions each is explained in great detail. It's a 40 buck app and once purchased you get free lifetime updates for the recurrent testing information.
Plus, now the FAA has released their official study guide hereFAA NEW Study Guide

I self studied and passed the Airman Knowledge test for Unmanned Pilot. There are many excellent videos posted on YouTube. Cyndy Hollman has a channel with some excellent videos on Airspace and on Sectional Charts.  Also Pilot Training Systems has a series of videos on YouTube. You should also study the FAA publications on UAV's.  part 107 Summary and Part 107. the Study Guide, etc.

Hello

I actually used a company called DartDrones and the FAA to study for the coarse. (I passed last Friday) It is a very expensive option. Like $250 The course is very basic but it does cover most of what the FAA provides but with videos and quizzes. In short everything you need to know is on the FAA website but... Its not laid out very well and you will spend a lot of time reading and sorting. Im not here to sell you on DartDrones but it will not hurt to at least check out there website and others like it.