A list to compile some of the best "meta" films out there. I'm going to be fairly liberal with the term and add examples of any type of film that blends layers of reality between the artistic product, it's production, and the reality in which we view that product. So it's not to be confused with the surrealistic type of reality blurring (although while not all surrealistic films are meta, meta films can be surrealistic) but more along the lines of anti-escapism (devices that make it clear you are watching a film). Films about filmmaking can be included to a certain extent (depending on the severity of how much filmmaking has to do with the film's content), films that break the fourth wall (although again I'm not including films that contain these examples to only a minor degree), documentaries that pose as fictional cinema or vice versa until reality is obscured, etc.

Refer to:

en.wikipedia.org/wiki/Metacinema

and

en.wikipedia.org/wiki/Metafiction

Recommendations are welcome.