Whats my theme

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Across
  1. 4. a windy sinuous shape
  2. 7. symbol AU
  3. 8. C Major
  4. 10. ABC series featuring Nathan Fillion
  5. 14. Zuko’s element
  6. 15. underground prison
Down
  1. 1. no bite
  2. 2. Gila
  3. 3. “one dance” Canadian artist
  4. 5. Female American rapper
  5. 6. card game for Sheldon
  6. 9. YouTube pop icon Mr
  7. 11. Sobe mascot
  8. 12. a short forceful breath
  9. 13. Slytherin seeker