Here are some online courses.
Dart Drones – $350 online $670 in person
Online course is currently available.
Drone Pilot Ground School – $299 online
It appears as if the course is currently available online.
Aerodrome – $250 online $895 in person
Online course is available.
UAV Ground School – $249 online (includes 2-year access to all online classes)
Course is available online.
Aviation Seminars – $429 two-day course in person
Drone Knowledge Test Prep – $20
Sarah Nilsson – Free
Just going from the websites, I like the Dart Drones offering. The curriculum as published looks like it matches closely and in detail the Part 107 exam knowledge requirements. The instructor faculty looks pretty good too.
UAV Ground School has a nice approach mixing video lectures with graphic and text aids, links to FAA and other resources, and a solid practice test. You can take a look at a lot of the materials and get a good feel for the course. Roger, you may find that the mix of different media tools may work for your learning style.
Drone Knowledge Test Prep seems to have a real good practice test.
Sarah Nilsson's offering is very comprehensive and for some learners may be all that's needed to master the material. I know that's the path I'm taking, and my test is scheduled for Aug 30.
You also may find that a course you can take in person in a classroom may be best. I would want to be sure that the course handouts are sufficient unto themselves for getting you ready for the test. A two-day lecture may or may not be enough immersion for all students. I know that I plan on putting in at least 40 hours of study.
Good luck to everyone!