The First, Second, and Third Books of Swords, Saberhagen. If you like that sort of thing. I re-read these to see whether I missed anything cool in Ardneh’s Sword. The refresher did clear up the otherwise-inexplicable pointless character from AS, but, if anything, made the latter work even more of a disappointment in retrospect. There’s not even the slightest hint, in the fairly explicit exegesis presented in the Swords books, of the direction Saberhagen would, twenty-odd years on, decide to retrofit into the saga. I can construct a somewhat tortuous chain of reasoning by which the two ontogenies are not outright incompatible, but the author should be shooting for a very satisfying click as all the pieces fit together, not "Well, if you interpret what Draffut said this way, I suppose it still makes sense…."
On their own, the three original Swords books are just fine, as is the Empire of the East before them. I don’t have any immediate intent to re-read the eight Lost Swords books.