Pretty much just 750 and 790. Some years are better than others. If you're only looking for a frame, the 750/790 is going to be lighter than a 700/730. The earlier, the better, in my opinion, so anything with lugs gets my recommendation. Can't say much about the later frames. A late 80s-early 90s 520 will also have the same geometry with nicer steel, just FYI, but it'll probably command a higher price and will have touring-specific braze-ons which you probably aren't looking for.