You can find more tales of Guto's races in 'Plwy Llanwynno: yr Hen Amser, Yr Hen Bobl, A'r Hen Droion' (Llanwynno Parish: its history, people and customs) by Rev William Glanffrwd Thomas 1888.
English translations are available:
- 'Glanffrwd's History of Llanwynno' by Thomas Evans 1950
- https://www.amazon.co.uk/Llanwynno-Treasury-Memories-Adaptation-Glanffrwd/dp/178281003X
There's even a song! https://m.youtube.com/watch?v=jeVLq-U4IoY