I can't help but wonder when I see lists of famous works that we know exist from classical antiquity, but are thought to be lost, does anything new of significance get discovered these days? Something like a lost chapter of Livy, a biography by Plutarch, or a play by Aristophanes?
I would think it must be very rare as almost every document from the era would have long since disintegrated. My understanding is the most writing from the world of classical antiquity is lost, unless enormous effort was undertaken throughout the ages to save it. Monks or some of the other tiny population of literate people had to recopy by hand everything they wanted to preserve every hundred years or so. And so any writing that does survive from that era is more like the 20th recopy by someone 1500 years later than an original from the time. As such, even if a new historical site is excavated, they might find pottery, but wouldn't find a treasure trove of ancient scrolls.
Is my understanding correct and that everything lost likely to remain lost, or does new stuff ever come to light? What was the most significant discovery in recent times along these lines?
The Archimedes Palimpset is an extraordanary example of finding information from the classical world. The original work was actually a copy several generations removed from it's original, written in 950AD, and had it's writing scraped off to hold religious texts. Modern scholars rediscovered it in 1920's, but academics only had access to it in the turn of the century, and only recently have we had the tools to make out most of what it actually says.
The Palimpset is collection of a few copies of Greek texts, but the most significant is several copies of original, Greek Archimedes works on arithmetic, geometry, and especially an example of what we'd call modern Integral Calculus, used to solve the volume of a few three dimensional shapes, and several fairly rigorous proofs.
That we have it is a miracle - even when we found it, a war intervened, it disappeared, the eventual possessor tried to auction it off privately, hidden in conditions bad for books, and later partially vandalized by a forger attempting to add value. This is work that was intended to be destroyed, since paper was precious, and it was the combination of someone who could recognize the significance of the text coming upon it at the right time that let us have it.
While I'd doubt we'd ever find, say, the rest of the Greek plays we know existed, or the works of all Pre-Islamic poets, but sometimes we're just flat out lucky and we get a chance to pry a snapshot of knowledge from the jaws of entropy.