Elestron is a lesser known child of Dôn, and presumably her consort Beli Mawr.

Elestron He is mentioned in the genealogical tract “Bonedd yr Arwyr”.

25. Plant Don o Arvon
Gwydion, Govannon, Amaethon, Hunawg, Idawl, Ienuydd, Elestron, Digant, Gyluaethwy, Kynnan, Hedd, Addien, Elawg, Arianrhod

Bonedd yr Arwyr

He is also mentioned in Llyfr Taliesin, the Book of Taliesin with his brothers.

I have been with skilful men,
With Matheu and Govannon,
With Eunydd and Elestron,
In company with Achwyson,

The First Address of Taliesin

Elestron: his name means “lily”