If you've come here with this question, the first thing I'll say is congratulations. You've worked your way through a lot of Magoosh GMAT practice-- nicely done!
But you're still hungry for more practice. Good for you. Where to go next? Well, let's look at the top sources of non-Magoosh GMAT practice exams.
First and foremost, you'll want to try some official GMAT practice exams, sections, and question sets. By "official," I mean GMAT practice tests made by the Graduate Management Admissions Council (GMAC), the same organization that makes the actual exam you see on test day.
GMAT practice tests from the makers of the real exam are guaranteed to be true to the test itself. You can get a number of practice tests and practice sections from the official GMAT books: The Official Guide for the GMAT, and the GMAT OG and Verbal Quantitative Review books. In the official online GMAT Prep store, you can also get extra computer-based practice GMAT tests in the form of "Exam Packs." Last but not least are the practice GMAT exams that you get for free with the official GMATPrep software pack from MBA.com.
Now, third-party unofficial GMAT practice tests can be a bit hit or miss. Making a really good practice GMAT test is tricky. However, there is one other unofficial GMAT prep source that Magoosh recommends: Manhattan GMAT. In fact, we like MGMAT so much that we incorporate Manhattan practice tests into our official GMAT study schedules! You can find MGMAT exams through Manhattan's GMAT books, courses, and free online resources.