Papers of John Morgan Howell of Aberaeron, 1871-1960, including exercise books containing a memorandum for 1871 and a history, in Welsh, of Dr Thomas Phillips, Neuaddlwyd, by J. M. Howell; books of press cuttings containing articles relating to Aberaeron, 1873-1931, operas, 1920-1960 (collected by G[eraint] M. Howell), and the poetry, 1889-1921, of Margaret Aeron Davies; and articles by J. M. Howell, 1897; family correspondence, 1888-1926, and miscellaneous letters and papers, 1875-1946; a volume of typescript copies of Christmas carols in Welsh composed by J. M. Howell, collected and bound by J. Seymour Rees, 1941; and a pedigree of the Howells family of Penybaily, parish of Llangunllo; together with some papers of his daughter, the late Mrs Nesta Poulgrain (née Nesta Howell), including a diary of a journey to Naples [by Mrs Poulgrain, 1937]; and exercise books, containing a copy of the diary and poetry (1918).

Notebook, 1959-1961, of Caradog Prichard, poet and journalist, containing a fragment of a diary, in English, 3 November 1959-26 January 1960 (ff. 3-14 rectos); 'A Scheme For A Daily Newspaper In The Welsh Language' (ff. 16-18 rectos); notes for, and fragmentary draft of, Un Nos Ola Leuad (1961) (ff. 18v, 19-23 rectos, 61v); numerous drafts of poems, mainly of parts of 'Cân yr Hen' from his ode 'Cymru'; and miscellaneous notes and personal memoranda.

Papers of J. Glyn Davies, mainly letters, many relating to antiquarian, academic and library interests, including 400 from Robert Scourfield Mills ('Owen Rhoscomyl'), 1903-1919, almost 200 from Jennie Thomas relating to Llyfr mawr y plant, 1920-1950, and 150 from T. Gwynn Jones, 1908-1947; papers of his family, including the Tanycastell Collection, 1821-1858; and manuscripts collected by him, including the Henblas manuscript (Welsh poems by various authors, 1664-1685) and the Gwallter Mechain manuscripts.

Papers of Brythonydd and others, [early 18th century]-1952, comprising essays and notes on Teifiside history, 1902-1909; notes on sermons and lectures; diaries, 1906-1923; transcripts of various historical, literary and religious material including Ystradyfodwg parish records, 1735-1930, and Howel Harris' diaries, 1738-1771; transcripts of poetry by Cardiganshire poets including Gwinionydd; letters, 1898-1952; vestry books and account books of Cenarth and Penbryn and other parishes, [pre 1798]-1876; records of Libanus, Treherbert including minute books, registers and account books, 1842-1946; papers of Benjamin Williams (Gwinionydd), including letters, sermons, 1855-1890, essays, notes and poetry; papers of David James (Defynnog), Treherbert, relating mainly to the column he edited in The South Wales News and including sermons and adjudications of his uncle, Benjamin Thomas (Myfyr Emlyn), 1875-1928; papers of John Morris Jones (Ioan Cunllo), John Thomas, Charles Davies, Thomas Cynfelyn Benjamin, Lewis Jones, Treherbert, Rees Price, David Price, Joseph Davies and Rhys Lloyd Jones, Troed-yr-aur, and others, consisting mainly of poetry, accounts, letters, addresses, notebooks and sermons, [19th century]-[20th century].

A holograph copy of the adjudication by T[homas] Gwynn Jones [professor of Welsh Literature, University College of Wales, Aberystwyth] on the four poems submitted for the chair competition at the Denbighshire Chair Eisteddfod [held at Denbigh, 3, 5, 6 June], 1922.

Llawysgrifau William H. Griffiths (Llinos Wyre), [1894]-1931, yn cynnwys tair cyfrol o dorion o'r wasg (NLW MSS 8298D, 8300-1B) ac un casgliad llawysgrif (NLW MS 8299E) o'i gerddi ac alawon. = Manuscripts of William H. Griffiths (Llinos Wyre), [1894]-1931, consisting of three volumes of press cuttings (NLW MSS 8298D, 8300-1B) and a volume of manuscript transcripts (NLW MS 8299E) of his poems and melodies.

Allbrintiau o bedair ar ddeg o gerddi a gyfansoddwyd gan Iwan Llwyd ar gyfer arddangosfa, 8 Ebrill-30 Medi 2000, yn Llyfrgell Genedlaethol Cymru, i ddathlu chwecanmlwyddiant dechrau gwrthryfel Owain Glyn Dŵr. Fe'u cyhoeddwyd yn Owain Glyn Dŵr 1400-2000 (Llyfrgell Genedlaethol Cymru, Aberystwyth, 2000). Ceir hefyd gywydd 'Teulu Owain Glyndŵr' nas cynhwyswyd yn y gyfrol.

Deunydd yn ymwneud â'r flodeugerdd Tro'r Haul Arno (1982), gan gynnwys rhagair i'r gyfrol gan yr aelod seneddol Dafydd Elis Thomas a llythyr oddi wrth yr Athro John Rowlands ynghylch cyhoeddi ail-argraffiad o'r gyfrol.