What were the Celtic royal family called?

As 'celtic' refers to a wide range of people speaking languages that belonged to the same family, and who had a similar culture, there is no single celtic royal family.

In modern time, the celtic nations refer to no less than 6 diffrent territories who have all had their own celtic traditions and/or languages survive. The 6 territories are Brittany, Cornwall, Isle of Man, Ireland, Scotland and Wales. As such, there is no single royal family here either.