Are targaryens the only Dragon Riders?

Related questions

1. Who is the hound related to?
2. How did Stannis die?
3. What happened to Volantis?
4. What is the meaning of Nisa in Urdu?
5. What does Nyssa mean?
6. What happened to the red comet in Game of Thrones?
7. How did Aegon Targaryen die?
8. What happened to the sword lightbringer?
9. How does the Hound die?
10. Is Berics sword lightbringer?

Tags

1. #valyrian
2. #known
3. #targaryens
4. #although
5. #dragon
6. #dragons
7. #surviving
8. #corpse
9. #night
10. #making
11. #dragonriders
12. #dragonlords
13. #viserion
14. #enslaving
15. #house
16. #reanimating