By my definition, a gender bender movie is a movie where a character who presents as one gender finds themself in a situation where they must personally present as the opposite gender. Classic examples are Mrs. Doubtfire and Just One of the Guys.
I really think this is the most complete list of its kind! :')
And of course I take suggestions.
I chose not to include movies with the following traits:
1. The gender bender aspect is a plot twist or reveal. If the audience doesn't know about the gender bender it just doesn't really fit the category. So no Psycho, sorry.
2. An actor/actress is playing a part of the opposite gender. While interesting, it doesn't figure into the actual plot of the movie. So no I'm Not There, sorry.
3. I don't consider transgender characters to be exemplifying a gender bender because transgender folk aren't "dressing up" or "trying to fool people", so ultimately it would be disrespectful to include such characters on the list. So no Transamerica, sorry.
4. Characters who cross-dress as a hobby or perform drag. The key words here are perform/hobby. These characters aren't actually trying to present as the opposite gender in their personal lives. So no To Wong Foo, sorry.
I haven't seen most of the films on this list so some movies may not meet the criteria above. I'll clean up the list as I see more of the movies.