The latest example: the Silmarillion material at Marquette. There's not a lot of this -- only five pages (two and a half sheets) -- and I've known about it for a long time, but I never really looked at it in detail before.
Basically, for those who don't know about this already, the material that came from Tolkien amounted to thousands of pages. A volunteer sorted it out into books not long after it arrived,* after which archivist Wm Ready put together a travelling exhibit of some more interesting pieces.** Then around 1978 two women re-processed the collection, establishing an exact count in which every draft of every chapter had its own folder and designator. And, in the process, they found two sheets of Silmarillion material that had somehow gotten in with the rest at least two decades before,, before it ever left England. And could now, after the publication of THE SILMARILLION itself the year before, be recognized for what it was. Taum Santoski got in touch with these two processors a decade or so later and tried to find out the location of these sheets within the LotR material but to no avail; while they'd been proud of the discovery they hadn't made any record of the details and no longer remembered where they'd been among those hundreds and thousands of pages.
As for the pages themselves, they were long ago identified as to which page belongs to which part of THE SILMARILLION by Taum, in his little 1983/84 Exhibition catalogue.
(1) The opening paragraphs of THE VALAQUENTA [SILM page 25]
[Marq. 3/9/36: 1a; item #44 in Taum's catalogue]
--the verso of this page (:1b) also contains Silm material, in this case drafting for disconnected individual lines about various of the Valar and a passing reference to AElfwine.
(2) The opening of Chapter III in THE SILMARILLION: "Of the Coming of the Elves"
[SILM page 47]
[Marq. 3/9/36: 2a & 2b; item #43 in Taum's catalogue]
--here we have two stages of drafting, one in ink and the other in pencil, both being variant texts of the same passage, curiously enough on opposite sides of the same piece of paper. Also odd is that the ink text looks to be the earlier, with the pencilled obverse version being closer to the text of the published book.
(3) a passage from "Of the Rings of Power" (the final section of THE SILMARILLION)
N.B.: This one I'd forgotten about, and didn't go and re-check today, so here I'm dependent on Taum's description of it and don't know what exact page of THE SILMARILLION this text corresponds to.
In any case, it's clear why this page wound up at Marquette: the back of this sheet features the scene in which Galadriel leads Frodo and Sam to her Mirror.
So there it is: only a fractional collection when considered against the great mass of LotR papers, yet a highly interesting little batch of documents. I'm glad to have the chance to see them again, after all these years.
current reading: the same.
current research: the earliest LotR Mss.
*i.e, Book I of FR, Book II of FR, Book III of TT, &c.
**this circulated until around the time of Tolkien's death, I gather, at which time it was discontinued so Marquette cd better safeguard the Mss.