Hmm, horror is not my main interest but 2 titles standing above the crowd IMO:
-"Night of the Devils" (Giorgio Ferroni)
-"House of the laughing windows" (Pupi Avati)
There are shitloads more, "Lisa and the devil" from Bava is great as well and of course the obligatory Fulci and D'Amato classics, I guess I don't need to mention them again here! :'(