White Dragons

The White Dragons live within the Frozen Tundra of the north and there they have remained. Even under Tiamat the White Dragons had been more beastial than their brethren and without her they have become rabid. They are now near wholly mindless as beasts with only a base instinct to hoard gold and jewels.
They roam the tundra either imn solitude or in small family units, plaguing travelers and nomads and fighting with the Frost Giants at regular intervals. Amusingly this has led to a signifigant increase in their numbers, as they avoid civilization for the most part and as such more often live longer. 
Some have been observed to have retained their intelligence, lamenting the fate of their people. One has even been permitted to live within the Roost, the notable exception to the Children of Bahamut's hatred of Chromatic Dragons, and he had to prove himself extensively to Bahamut and Aryzen personally.
The feral dragons have been observed to be able to be tamed, albeit with extreme effort.