Seasmoke is a silver-grey dragon who was hatched to Rhaenyra's thought-dead first husband Laenor Velaryon. Both the dragon and rider participated in the War for the Stepstones before Seasmoke ...

A silver-gray, young dragon ... He was ridden by King Jaehaerys Targaryen I and hasn’t had a rider since. The dragon is unclaimed but after the encounter with Daemon, likely Team Black.