We are pretty well placed to estimate the number of Greek NT manuscripts that there are. The Kurzgefasste (Kurt-gefasste!) Liste and supplements give accurate information. Of course we don't know what to expect from ongoing Oxyrhynchus publications, and Dan Wallace estimates there are about 200 more to find in libraries. Perhaps the number may in a few decades hit 6,000.
As far as I know there is no official list of LXX manuscripts, though I understand that a chap in Sydney was preparing one (anyone know any more?). How many mss are there?
What guestimates would people make for the following?
Hebrew Bible mss