Mostly our closing costs have been pretty transparent. The loan processing bank (who isn't the underwriter, so gets none of the interest) charges a loan initiation fee. The title company charges a processing fee (to research the title history, including a trip to the court house to pull physical records). The assessor charges a fee. The realtor get a commission (which he worked pretty hard for). The inspector charges a fee.
Beyond that, no other fees listed... and the rest of the closing credit we got from the seller goes towards reducing our mortgage principal.