Let’s talk about everything to do with 한자! 
Websites
- Korean Hanja Dictionary
- Naver Hanja Dictionary
- 한자사전
- Tuttle Advanced Korean Workbook with Hanja vocab list, stroke order and reading practice
(Advanced Korean PDFs)
Books
- Your First Hanja Guide | L15
- Handbook of Korean Vocabulary: A Resource for Word Recognition and Comprehension | L30
Note: This is now a wiki, feel free to add your recommendations directly to the list above.
