Hitler is very famous in fiction world and SFF is no exception. For example, Captain America Comics has shown Hitler countless times since early 40s. But, I am only interested in the movie and TV series. Some examples:
In the episode Let's Kill Hitler of Doctor Who (2005), Hitler was shown.
In an episode of Justice League (2001) in which Justice League travelled back in time to restore timeline, Hitler was shown frozen in the end.
Note: Mere mention of Hitler (like that in Captain America: The First Avenger movie) won't be counted.