Are any online courses worth college credit, other than SSD 1 and SSD 2?

I concur with CSM Darieus ZaGara, it very much depends on the school and degree program you are applying the online course to. There are no courses that automatically equal a free floating college credit that you can apply. Even when you look at your Joint Service Transcript, the ACE evaluations are only recommendations to any particular school you send your transcript to; the school can choose to convert the recommendation to a college credit or leave it out altogether.

I just did a search and found this website that seems to directly cover your question. It's 4-years old, but may point you in the right direction. There are two links within the article, one of which lists a table of courses and their recommended college credit equivalent.

http://www.ezarmypoints.com/army-correspondence-courses-worth-college-credit/

If you're taking classes online, why wouldn't you take college classes that lead toward a degree or certification. It's free.

It depends on where you are referring to online, military sites, or civilian sites? Military almost any that provide a grade or certificate of some sort, and for civilian as well. However, based on your degree program and level of education determines whether they qualify as electives or core credits, if at all. Speak to your education counselor. Thank you for your service.