You might try http://www.livius.org/ . It is an educational institute of some sort out of the Netherlands, I think. They cover a lot of ancient history but traditionally they seemed to have a focus on the East (from a Mediterranean-centric view). I follow one of their researchers on social media and he seems to take frequent trips out there.

It is encyclopedic instead of comprehensive, but you might find some good information or ideas for other sources.

Have you checked out the book list? Many of those books are common, and can be gotten from your local library.

Also check out the etana core texts, academia.edu and google scholar for specific questions you might have. As I recall, khan academy had something, but I've never checked it out.

The medium of the scholarship is still books and papers, for better abd worse. I would start by checking out van de meiroops introduction to the subject.

I'm on mobile, but hit me up if you'd like me to expand on anything.