I haven’t listened to very many of these yet, but this includes lectures that appear to be the basis of several of his books. These include True Spirituality, No Little People, Joshua and the Flow of Biblical History, Genesis and Science, A Christian Manifesto, The Mark of the Christian and The Finished Work of Christ, among others. I must confess that I am less familiar with his well known apologetical works than I am with some of his others but I’m sure much of that material is there in embryonic form as well.
Overall, a wide variety of topics are covered, from cultural analysis, theology in general (including a series on the Westminster Confession of Faith), apologetics, the arts, etc. There are also a good many lectures on eschatology, including an exposition of the book of Revelation. It is well known that Schaeffer was premillennial, which was not uncommon among Presbyterians of his day, particularly among those of his background. The titles of some of them seem to indicate that he was pretribulational as well. But those lectures appear to be from the early 1960’s so I don’t know if he ever changed his views as did some others like James Montgomery Boice, for example. I haven’t read that much of Schaeffer’s work, but I hope to remedy that soon. However, I have noticed allusions to a future for Israel in some of his writings that were published in the 1970’s. I do think it’s interesting that a leader who was known for teachings on cultural and other issues would have taught so much on prophetical themes. But most if not all of those lectures were from the early 1960’s, prior to him becoming a popular evangelical leader in the United States and beyond.
There is also a large amount of video material available online as well, perhaps most notably the film version of How Should We Then Live?