I won’t even attempt to describe the meandering thought trail that led me to this thread, I’ll just plunge right in.
In an old issue of Fantastic Four (when Frankie Ray discovers her powers), Reed makes a comment about calling their friends at Marvel about changing the title of the comic to Fantastic Five.
In an even older issue of Amazing Spider-Man, Spider-Man mentions a promo deal he entered into with The Electric Company to produce a “Spidey” comic.
Patsy Walker, a.k.a. Hellcat, showed her fellow Defenders issues of various comics in which she was featured (and which were supposedly created by her mother) in an issue of The Defenders.
Any other comic book characters you can think of who are stars of comic books within their own continuity?
I’ll hear discussion on whether to include She-Hulk on this list, considering that she was aware of her own existence as a comic book character in her second series (Sensational She-Hulk) but may not have been the star of a comic book within that series’ continuity. Same would go for the original Blonde Phantom (who starred in her own book in the 40s; I don’t recall from her appearances in Sensational when BP became aware of her comic book status). She-Hulk also threatened to rip up people’s X-men comics if they didn’t buy her book but it’s unclear whether she ws referring to books that existed within her continuity or ours.