To get a comprehensive list of his work, you may want to try these resources:
* IMDb (Internet Movie Database): This is the most common resource for finding information about actors and directors. Search for "Kostas Hardavelas" on IMDb.
* Greek Film Archives: Many Greek film archives and websites may have information about his work.
* Greek Movie Magazines and Publications: Online and print publications specializing in Greek cinema could contain details about his career.
Remember that finding information about international film projects, especially those in languages other than English, can sometimes be challenging. Keep researching and be patient!