Broadly defining dumplings as filling enclosed by dough, they seem to exist in most cuisines. And they are always the best. Add any exciting ones I've never heard of! Thanks to @jordan for the help.
  1. Khinkali (Georgian)
  2. Vareniki (Ukrainian)
  3. Manty (Central Asian)
  4. Pelmeni (Russian)
  5. Kari pap (Malaysian)
  6. Pierogi (Polish)
  7. Empanadas (Mexican)
  8. Gyoza (Japanese)
  9. Egg/spring roll (Japanese/Thai/Chinese)
  10. Pau (Chinese)
  11. Pot sticker (Chinese)
  12. Popiah (Philippine)
  13. Ravioli (Italian)
  14. Samosa (Indian)
  15. Hot pocket ('Murican)
  16. Corn dog ('Murican)
  17. Wontons (Chinese)
    Suggested by @eatthelove
  18. Momos (Tibetan)
    Suggested by @eatthelove
  19. Xiao Long Bao (Chinese)
    Soup dumplings
    Suggested by @eatthelove
  20. Mandu (Korean)
    Suggested by @eatthelove
  21. Kreplach (Jewish)
    Suggested by @eatthelove
  22. Buuz (Mongolian)
    Suggested by @sloan
  23. Madombi (Botswana)
    Suggested by @crossetter
  24. Souskluitjies (South African)
    Suggested by @crossetter
  25. Braaibroodjie (South African)