USMLE preparation books/materials
Thanks for your question! In the Omaha Public Library system we don't appear to have any test prep resources specific to the USMLE - given the complexity of the exam itself and its moderate level of specialization, and the expense and complexity of study guides for the 3 parts and various skills, it may not be a good fit for our collections as a public library. Even our online test preparation resources like Learning Express strike out on the USMLE.
Now, that said, I think you may still have access to some quality resources. USMLE.org has a fairly robust section of practice materials. I'm assuming from your unomaha.edu email extension that you likely have access to materials and databases from the UNO Criss Library - it looks like they have some solid options in their print and ebook collections that might meet your study needs, though I'm sure there's a lot of competition for them.
Thanks again for your question! Although we don't have quite what you're looking for, I hope you'll be able to find some useful preparation materials. Feel free to call 402-444-4800 with additional questions, or contact the Criss Library directly at 402-554-3206.