Llythyrau oddi wrth David Bell, 1951, 1958-1959, yn trafod materion celfyddydol a'i iechyd; llythyrau oddi wrth meddygon, ei wraig a'i deulu, yn trafod ei salwch, 1958-1959; ynghyd â threfn ei wasanaeth angladd, a thaflenni teipysgrif yn ymwneud â materion celfyddydol.

Papers, 1843-1991, of the artist R. L. Gapper, including correspondence, plans and other material relating to artistic commissions undertaken by him; records and correspondence accumulated through his work as an administrator and adjudicator with the National Eisteddfod, and also as a lecturer in the University of Wales; and personal papers, including diaries and correspondence. Many of R. L. Gapper's own letters remain in the archive, since he often made copies of the letters he sent.

Correspondence with Welsh artists, art patrons and administrators of art institutions, together with annotated catalogues, ephemera and press cuttings, almost all relating to Winifred Coombe Tennant's activities as a patron of Welsh art and art in Wales. Throughout this group of papers are notes added by Alexander Coombe-Tennant.

Minutes of the Cymmrodorion council and other committees, 1873-1970, secretaries' papers, 1873-1958, 1996, librarians' papers, 1904-1939, papers relating to the Society's public activities, 1876-1988, financial papers, 1879-1954, membership papers, 1873-1933, and papers relating to its constitution, 1951-1954.