The music manuscripts of the composer David Harries, 1952-1995, comprising mainly drafts and scores of chamber and instrumental music, orchestral music, choral and organ, and voice and piano arrangements.
A second donation made in August 2021 contains further music manuscripts of David Harries, 1953-1993, and includes works by Harries' contemporary William Mathias (1934-1992) in addition to Harries' own compositions of chamber and instrumental music, orchestral music, choral and organ, and voice and piano arrangements.

Musical manuscripts of the composer Grace Williams, [1928]-1992, including orchestral scores of her works, [1932]-1973, concertos for solo instruments and orchestra, 1950-1973; scripts and scores for narrator and orchestra, 1946-1963; incidental and chamber music scores, [1930s]-1970; choral music scores [1928]-1975; film and incidental music, 1948-1970; personal and miscellaneous papers, 1826-1936; and poetry by Vivien Cutting, 1947-[1967]; note on the papers, by A. J. Heward Rees, 1997.

A scrapbook kept by Hubert Davies (1893-1965), composer and musician, born at Abersychan, including papers relating to his time as a student of the violin at the Royal Academy of Music, concert programmes, photographs and photocopies of articles on music by him published in the Western Mail, together with a list of his manuscripts deposited at the BBC Library, Cardiff, and tributes to his widow Mrs Hannah Davies (d. 1970).

Music manuscripts and papers of the composer and teacher, Gilmor Griffiths.

Music manuscripts and personal papers of the composer William George, 1865-1920, including anthems, [1900]-1920; hymns, 1894-1920; part-songs, [1901]-1908; marching songs, 1901-1913; secular music, 1910-1917; duets, 1913-1919.