Shake and Bake or LarePrep are good.
Only offers these practice exams online. There is nothing for you to print or download to save (can't even copy paste) so using this source as a study aid requires a lot of time. That said this is the most up to date resource out there, with the fewest errors. They give shot explanations of answers.
These resources are a little more out of date but the information is still good and you get a pdf you can print and highlight and make notes from and so on. They also offer a more a thorough explanation of the answers.
Practice tests are sometimes wrong. Any time you get a question wrong, or you guessed on a question you got right, you should go back and research the topic. Find a site-able source. Practice exams are about building your test taking stamina. Get the most out of them by coming up with questions that would have given you the other answer choices.
Good luck!