My sense is that this would be a very slow and painful survey to undertake... but here are a few leads on where you might find people who have already done it.
There's a Journal of General Education published by Penn State University Press, and it probably has articles about recent thinking or trends in this regard. In particular, it published an article on how the University of California at Merced designed its general education curriculum, as a research university that first held classes in 2005. There's a lot there about different philosophies of designing general education.
Another possible source of a large-scale comparison of general education curriculum is cross-campus research undertaken for other purposes, such as using the National Survey of Student Engagement or the Collegiate Learning Assessment. Research focused on the first year of college may also mention this.
Writing programs seem to be especially well-studied, and in general there seem to be trends toward designing early coursework to improve skills (such as writing or data literacy) rather than to impart specific knowledge.
Finally, there's a trope that every (American) university always copies Harvard, so you if you do not find a ready-made list of general education classes across schools, you could make one based on your state schools, a few regional rivals, and Harvard. ;)