Here are some useful sites I have found. One I can't find at this time had multiple specialty top 50's (for free), although the third one on the list has top 20 for most specialties.

http://www.aapc.com/ICD-10/codes/index.aspx
http://static.aapc.com/ppdf/ICD9-ICD10-reference-sheet1.pdf
http://www.pulseinc.com/top-20-icd-9-icd-10-conversion-charts-specialty
http://www.icd10data.com/ICD10CM/Codes

Wendell
Pediatrician in Chicago

The patient's expectation is that you have all the answers, sometimes they just don't like the answer you have for them