The Avengers are off to see the Wizard
When it comes to Wizard of Oz "how did they make that connection?" mashups, it may be impossible to ever top , which scored the entire movie to the classic Pink Floyd album.
But we can at least say The Avengers of Oz: The Age of Tin Man is the best one not inspired by use of pot or hallucinogens (or so we assume). The Tin Man has never been so terrifying.
Also, if you ever wondered what the Cowardly Lion would look like in a Thor costume, now you know. (Putting Alan Alda's head on Hawkeye was a nice touch, BTW.)