Surviving manuscripts of Franz Paul Lachner's 2nd symphony, since this was raised in another thread...
His 2nd, in F, was performed in 1834 in Vienna according to the 5 March 1834 A.M.Z. p.159 (as digitized and available @ Google Books; what may have been the premiere of symphony 3 is mentioned in an August 1834 issue on page 585.) I think RISM mentions manuscript material of the 4th symphony - ah, yes it does (the new RISM interface qv makes it a little harder to find but this is a link to the autograph score (https://opac.rism.info/search?id=456081788)...) (125f - so 250 pp I guess.)
Ah, here now... this seems to be a link to the autograph score of no.2 (https://opac.rism.info/search?id=456081789) @ Munich dated 9 February 1833. (120f - 240 pp, I guess.)
Hopefully there might be some interest, despite the composer's already-noted failure to be as good as Schubert (let alone other tauter composers), in dusting off and recording these works , or at least having a look at them...
(and then there's those manuscripts, mostly but not entirely juvenilia, by Hiller @ Frankfurt, that also seem - to me anyway - intriguing. Actually, GUF(rankfurt) has digitized a fair number of ... ok, that's offtopic already. Though some of it might be by Lachner, I should check. :D )
Thanks to Cypressdome for uploading the score of symphony no.4 to IMSLP.
Edit: and symphony no.2 op.44 too.