The FAA Part 107 test is not easy.  At the time of posting this, there is currently a 24-month recurrent Part 107 test as well.  You can learn more about FAA Part 107 on the FAA’s official website here:

FAA Part 107 Website

Being an avid drone hobbyist since the early days of drones, I felt inclined to become a Part 107 pilot to better enhance my drone knowledge and safety.  When I took and passed the initial Part 107 exam during 2016, I quickly learned that the exam was more difficult than I thought.  For that reason, I felt obligated to share the FAA Part 107 preparation materials that I used to prepare for the initial FAA Part 107 exam, as well as the revised for 2018 versions of the materials that I used to prepare for the 2018 Recurrent Part 107 exam.  These materials should obviously not be used in place of the FAA-provided materials but they helped me to better prepare for the tests.

This book provides an an excellent set of knowledge and practice questions.  It’s available in digital format too but I recommend this paperback version:

Available on Amazon.comRemote Pilot Test Prep 2019: Study & Prepare: Pass your test and know what is essential to safely operate an unmanned aircraft – from the most trusted source in aviation training (Test Prep Series)

Understanding aeronautical charts is a must!  Pay close attention to colors, symbols and all knowledge within:

Available on Amazon.comASA Airman Knowledge Testing Supplement – Sport Pilot, Recreational Pilot, and Private Pilot

In addition to the two above books, I highly recommend purchasing the following app to function as an FAA Part 107 on-the-go practice test tool:
Prepware Remote Pilot App

In closing, my best advice is to expect to fail the Part 107 exam.  It’s not easy.  I’d suggest knowing all FAA-provided inside and out, and completing as many practice tests as possible prior to scheduling your FAA Part 107 exam.

This is where to register for the FAA Part 107 exam:
Computer Assisted Testing Service (“CATS”)