Several dear,
Exbrayat �s characters in books : Romeo Tarchinini (the Veronese detective for who all death is due to love...) and Miss Imogene Mc Carthery (the Scottish single retired woman who worked at the Admiralty in London) very bad tempered
Agatha Christie �s characters : Hercule Poirot (the Belgian man always well-dressed) and Miss Marple (the single old woman who is able to gather so many clues and information).
Of course Sir Arthur Conan Doyle �s Sherlock Holmes and his friend Dr Watson.
The famous TV ones : Columbo, Kojak for example.
There is a very adorable one : Rex, the detective dog in an Tv Austrian series.
Hope this will be useful.