THE DEAD SEA SCROLLS are on the WSJ's list of The World’s Top Five Treasure Troves, inspired by that recent discovery of vast treasure in the Sree Padmanabhaswamy Temple in Kerala, India.
The list looks about right to me. I would put the Cairo Geniza and the Ugaritic texts in a top-ten list. The treasures of the Copper Scroll (follow those links) would perhaps belong on the top-ten list too, if they could still be found, which is very unlikely.
Also, here's something recent on Massekhet Kelim (The Treatise of the Vessels), an apocryphal account of the fate of the Jerusalem Temple treasures.
I have noted some manuscript treasures from Kerala here (and links) and here (Cochin is in Kerala). (No word so far on any manuscripts in the Sree Padmanabhaswamy Temple trove.)