When it comes to Old Testament courses online, some readers may wish to study more specialized or advanced topics. However, many of the online courses that are available, particularly on this site, are directed toward more general learners. Yet there is a possible avenue for those that wish to study more advanced topics. The Society of Biblical Literature has published example course syllabi for a significant number of topics related to the Old Testament, New Testament and beyond. As far as I know, no membership to SBL is necessary since I was able to view the syllabi without logging in. These syllabi can be useful for those wanting to study particular topics on their own because there are often book recommendations, a reading schedule, course handouts and more.
As an example, a person may wish to study the idea of violence in the Old Testament and other sacred texts in detail. It is unlikely that someone will find an online course devoted to this topic; however, the SBL syllabus page includes a link to the course Sacred Texts and Violence taught by Dan W. Clanton, Jr. at Arapahoe Community College. This syllabus contains a considerable number of texts devoted to the topic and a reading schedule. I have glanced over the reading schedule, and it appears to me that anyone who simply followed the readings would get a very thorough introduction to the topic, much better than if one were to randomly choose a book on the topic from Amazon. So, if you are interested in studying more advanced topics related to the Old Testament be sure to check out the syllabi HERE.