The Tuatha Dé Danann king who had a hand made of silver was Nuada, also known as Nuada Airgetlám.
Nuada was the first king of the Tuatha Dé Danann. During the First Battle of Mag Tuired, he lost a hand or arm in combat, making him physically imperfect under the laws governing kingship. Because of that injury, he temporarily gave up the throne.
The physician Dian Cécht made Nuada a fully functional hand of silver. In later versions of the story, Dian Cécht’s son Miach helps restore Nuada’s original flesh and blood, allowing him to reclaim kingship.
The epithet Airgetlám means “silver hand” or “silver arm.” Nuada is also linked with the British and Welsh figures Nodens and Nudd, and is sometimes compared with other one-handed Indo-European figures, including the Norse god Týr.