You could read about Balerion the Dread.
Game of Thrones Season 3, Episode 10
But in the beginning, when it was home
to Balerion the Dread,
Game of Thrones Season 7, Episode 7
On the back of his dragon,
Balerion the Dread.
Game of Thrones Season 3, Episode 10
forged in the fiery breath
of Balerion the Dread.
Game of Thrones Season 3, Episode 6
Balerion the Dread.
Game of Thrones Season 7, Episode 2