Most Powerful Dragon in Game of Thrones: House of Dragon

Prince Daemon Targaryen (Matt Smith), the brother of King Viserys, rides Caraxes the Blood Wyrm.

1. Caraxes

Princess Rhaenyra Targaryen, who is King Viserys's designated heir, rides Syrax the she-dragon (Paddy Considine).

2. Syrax

Along with Balerion and Maraxes, Vhagar was one of the three legendary dragons that initially overran Westeros. 

3. Vhagar

Rhaenys Targaryen, the cousin and uncrowned monarch of King Viserys I, is riding Meleys the Red Queen.

5. Meleys

The fabled dragon Balerion the Black Dread is credited with helping Aegon the Conqueror conquer Westeros. He passes away from old age before the Dance of Dragons because his shadow is so enormous that it may cover a whole town.

6. Balerion

Daeron Targaryen, the eldest of Queen Alicent's sons and the brother of Aegon II and Aemond, rides Tessarion the Blue Queen, a she-dragon made of cobalt and copper.

7. Tessarion

Prince Jacaerys Velaryon, who according to legend is the son of Laenor Velaryon and Rhaenyra Targaryen, rides Vermax.

8. Vermax

Helaena Targaryen, the sister-wife of the Iron Throne aspirant Aegon II and the daughter of King Viserys I, rides an elderly she-dragon named Dreamfyre.

9. Dreamfyre

The daughter of Daemon Targaryen and Laena Velaryon, Baela Targaryen, rides a young dragon named Moondancer.

10. Moondancer