Yes, frequency rankings of letters based on their recurrence exist for many languages, including Romanian. Analyzing letter frequency is especially useful in cryptography, linguistics, and natural language processing tasks. Here is a rough frequency ranking for Romanian, based on corpus analysis:

1. E

2. I

3. A

4. R

5. N

6. T

7. U

8. O

9. S

10. L

11. C

12. D

13. P

14. M

15. Π(or  - both represent the same sound but differ based on spelling rules)

16. V

17. F

18. Z

19. B

20. G

21. H

22. Ș

23. Ț

24. J

25. X

26. Q

27. Y

28. K

Romanian also includes specific diacritics like Ș (S-comma), Ț (T-comma), Ă, Î, and Â, which can slightly affect letter frequency distribution, especially in more formal texts. These ranked letters and special characters are essential when working with Romanian text at the character level to handle diacritics accurately.