This content was born from an effort to help a new ham that had reached out. This request spawned me to work on the ARA site, and maybe put a list of different options that I had used or was already familiar (W5YI.ORG, ARRL.ORG, and KB6NU.COM), or that I found on the Internet. Personally, I really like KB6NU's books -- very helpful through my last two examinations (Tech and General); I just recently purchased the Extra edition.
When the ARA holds its Technical classes, we usually use the books from W5YI. They are well written books that help to teach you in a way that works with the classes that we hold. The ARA has no affiliation with W5YI other than we like thier books. Personally speaking, *I* have no affiliation with KB6NU, either.
As I was making my list of different options (a.k.a. reinventing the wheel) I stumbled across a blog fom HamStudy.org. Once I looked at that page, I stopped -- this one URL (below) includes everything that anyone would ever need to get started. In fact, that blog contains many more than than the ones I had listed.
If you would like to suggest a link that is NOT on their list, you may do so by logging into the site and commenting. If you do not yet have an account at W3CWC.ORG, you can click here to register. Please note that to avoid bots, part of the registration process is manual, and it may take a day or two before you are approved.
If you have a smart phone you may also want to visit the app market associated with your phone and search for "Amateur Radio Test free" to see what options they have available. I started with a free version, but upgraded to the paid version a little later. It is nice to have the ability to study at any given moment. If Wi-Fi and/or mobile data might be an issue for you, then you will want to try and get one that downloads the entire question pool rather than requiring a data connection. In fact, that is why I got the paid version.
I hope that this page helps; I am looking forward to other suggestions in the comments.