Manuscript orchestral score (Parts I-III) of 'Gwas y goruchaf', a cantata for mixed choir and orchestra, composed at Treadam, January and February 1969. Together with chorus score (Parts I-III), vocal score with piano (Parts I-III), and orchestral parts. Published Magor: Mansel Thomas Trust, Ref: MT080 [1998?].
Manuscript full score, photocopy of original short score of 'Salm 24' ('Y Brenin-orchfygwr'), for brass band, choir and baritone soloist; together with a manuscript chorus score, and brass band parts. Published Magor: Mansel Thomas Trust, Ref: MT078 [1998?].
Photocopy of manuscript score (with English words) of Grace's (his eldest daughter) composition with harmony by Mansel Thomas.
Two manuscript orchestral scores (old and new orchestration) of 'Y bardd' (words, R. Williams Parry). Published Llangollen: The Gwynn Publishing Co., 1945.
Manuscript orchestral score of 'Dewiniaeth Olwen' (words, Elfed), composed at Cardiff, September 1950. Includes orchestral parts and the vocal score 'Olwen'. Published Magor: Mansel Thomas Trust, Ref: MT126 and MT226 [1998?].
Manuscript score of 'Gwyn ap Nudd' (words, Elfed). Published : Gwynn.
Bound copy of a manuscript vocal score of 'Caneuon Siôn', (deuddeg o ganeuon i blant) a set of twelve songs in the original keys (text by Thomas Rowland Hughes). Titles: Siôn, Y Lôn Bell, Siôn a'r Ieir, Yr Eos, Peth fel 'na ydi'r Iâr, Siôn di Siôn, Dau dderyn to, Ble Mae Siôn, Trowsus Hir, Y Ceiliog, Siôn yn Jêl a Lol. Published: Mansel Thomas Trust, Ref: MT30 and MT31.
Manuscript vocal score of 'The inner light', one of the 'Five settings of poems' by Idris Davies = 'Pum cân': cerddi Idris Davies. Published: Mansel Thomas Trust, Ref: MT151.
In the sun's light that knows no setting,
Manuscript vocal score of 'In the sun's light that knows no setting' (words from Thomas Williams, Bethesda, transcribed by R. S. Thomas), with manuscript sketches and working notes by Gareth Griffiths.
Manuscript vocal score of 'Marguerite' (words by William Morris). Published: Mansel Thomas Trust, Ref: MT143 and MT230.
Manuscript vocal scores of 'Raider's dawn' (words by Alun Lewis). Original vocal score and two vocal scores (one photocopy) in a lower key. Published: Mansel Thomas Trust, Ref: MT158 and MT200.
Manuscript vocal scores of 'Rhymney' one of the 'Five Settings of Poems' by Idris Davies = 'Pum Cân': Cerddi Idris Davies. Original vocal score and copy (photocopy) in a lower key with additional markings by the composer. Published: Mansel Thomas Trust, Ref: MT150 and MT151.
Manuscript vocal score of Roland's [Mathias] and Mansel's "Pop".
Photocopy manuscript vocal scores of 'The Secret People' (words by A. G. Prys-Jones). Copy of the original score with corrections inserted by the composer, with a second manuscript of a lower transposition copied by Terence Gilmore-James. Published: Mansel Thomas Trust Ref: MT160 and MT290.
Photocopy of the original manuscript vocal score of 'Taliesin' (words by R. S. Thomas), for male voices. Published: Mansel Thomas Trust Ref: MT142 and MT198.
Photocopy of the original manuscript vocal score of 'Rob Robin' (words by A. G. Prys-Jones). Song No.3 of the "Three Songs for Joanna". Published: by Gwynn.
Manuscript vocal scores of 'Songs of Sleep' numbers 1 and 2 (words by Alun Lewis). Includes vocal score for each song (Number one is a photocopy). TPublished: as 'Two Songs of Sleep' by Mansel Thomas Trust Ref: MT165 and MT196.
Original sketches of 'Martin Luther King song'. Incomplete sketches from the period following his stroke in 1979.
Original manuscript orchestral score of 'Dacw Mam yn dwad', arranged for voice and orchestra. Also, a copy (photocopy) score and orchestral parts. Published: Mansel Thomas Trust, Ref: MT041.
Manuscript vocal score of 'Pan own i'n rhodio', for voice and piano. The Aberpergwm version, arranged by Mansel Thomas. Published: Mansel Thomas Trust, Ref: MT040.