Here is a list of Italian train stations, big and small, I came upon by pure serendipity. It may be of use to you in planning a trip to Italy if you intend to move around mostly by foot and train, as I so often did back in the day. The list is mostly organized by region alphabetically. The top two regions for tourism are Toscana (Tuscany, of which Florence is the capital) and the Veneto (of which Venice is the capital). They will be toward the end of the list.
Be aware that many of the smaller stations have very limited service.