It can be a shock, sometimes, to remember that not every writer is extant in a single manuscript. That shock just hit me, when I decided, in a weak moment, that I would “just” have a quick search in the British Library Manuscripts catalogue for works by Chrysostom.
I’m looking for copies of the ancient Latin translation of De Severiano recipiendo, in truth. But since I wasn’t specific, I got the lot.
Boy did I get a lot! 103 hits, to be precise. Mostly homilies on scripture.
Mind you, the quality was rather low. Arundel. 542 has a catalogue description which is plainly the result of uncorrected OCR. I don’t mind; but I’d like to see the raw image! On the other hand, someone has indexed the authors out of this mess with some skill and effort — well done! The ms. also contains some homilies of Severian of Gabala at the end, it seems.
I drew blank, but it’s a reminder that finding stuff by Chrysostom in all this mass will not be easy.
I haven’t looked much for Latin in the past, but the old catalogs can usually be found online. I think the Bodleian’s collection was cataloged in the middle of the 19th century. A search at Archive.org for “catalogi codicum manuscriptorum bibliothecae” brings up two results. Once you find the ms, you can at least see what the entry looked like pre-OCR.
If you’re looking for Greek stuff, then the Pinakes database by the IRHT in France is invaluable.