Regardless of what this list means to many of you, I keep receiving requests for information on the psychology of superheroes, so many that it's helpful to be able to provide this list as a reference for those who do need it. A lot of high school students, college students, magazine writers, bloggers, and journalists of other kinds have asked me about superhero psychology in recent years. Recently there has been a surge in the number of those requests. That's a good thing. It's wonderful that students and writers want to relate incredible heroes to real psychology and that educators and editors are increasingly willing to let them. Frivolous as that may seem to many people, we can often take a harder look at reality through the filter of fiction, especially fantastic fiction. Throughout our lives, we learn many things through contemplation of fictional examples. I want to help the students and journalists interested enough to write about these things.
Previously I compiled a list of books by psychologists and a couple of psychiatrists using psychology to look at specific popular culture topics (books, movies, or television series). Some of those works look at superheroes, but others do not.

• Geek Psych Library from Mad Men Reality to Twilight Fantasy.

Now for the list of resources to help anyone writing about the psychology of superheroes or simply interested in learning about it. I welcome suggestions on what to add to this list. This is meant to be a list of resources, so I don't mind revising the list as needed.
Books. Except for the first item, all of these books are by psychologists.

• Does This Cape Make Me Look Fat? Pop Psychology for Superheroes (2006), by Chelsea Cain & Marc Mohan.
• Using Superheroes in Counseling and Play Therapy (2006), by Lawrence C. Rubin.
• The Psychology of Superheroes (2008), edited by Robin Rosenberg.
• Batman and Psychology: A Dark and Stormy Knight (2012), by Travis Langley.
• Our Superheroes, Ourselves (2013), edited by Robin Rosenberg.
• Captain America vs. Iron Man: Freedom, Security, Psychology (2016), edited by Travis Langley.
• Superhero Therapy: Mindfulness Skills to Help Teens and Young Adults Deal with Anxiety, Depression and Trauma (2017), by Janina Scarlet.
• Wonder Woman Psychology: Lassoing the Truth (2017), edited by Travis Langley & Mara Wood.

This list leaves out CreateSpace books and other self-published works simply because they can be difficult to evaluate, and including some while excluding others could be unfair. That doesn't mean self-published items might not be worth your while.
Paul Zehr's books cover a combination of physiology, neuroscience, and psychology.

• Becoming Batman: The Possibility of a Superhero (2008), by E. Paul Zehr.
• Inventing Iron Man: The Possibility of a Human Machine (2011), by E. Paul Zehr.

I know of only one that is specifically a psychiatric text about superheroes.

• Superheroes and Superegos: Analyzing the Minds Behind the Masks (2009), by Sharon Packer.

The first of these next two books, filled with comic book writer/editor Danny Fingeroth's speculations and observations about how people think about superheroes, is the work that made me think, "I want to write this kind of book." The second, by a pair of lawyers, includes many relevant issues, most notably sanity and insanity.

• Superman on the Couch: What Superheroes Really Tell Us about Ourselves and Our Society (2004), by Danny Fingeroth.
• The Law of Superheroes (2013), by James Daily & Ryan Davidson (based on their blog, Law and the Multiverse).

Books from Relevant Fields. I'm not going to compile a list of every superhero book by scholars in other disciplines, but I will offer one example from each so you can consider looking in those areas as well in case they seem sufficiently connected to your topic.

• Philosophy. Batman and Philosophy: Dark Knight of the Soul (2008), edited by Mark D. White & Robert Arp.
• Political Science. War, Politics, and Superheroes: Ethics and Propaganda in Comics and Film (2011), by Mark DiPaolo.
• Religious Studies. The Gospel According to Superheroes: Religion and Popular Culture (2nd ed., 2006), by B. J. Oropeza.

Chapters. Even though these books are not primarily about psychology, they do include some chapters that are.

• The Many Lives of the Batman: Critical Approaches to a Superhero and His Media (1991), edited by Roberta Pearson & William Uricchio.
• Batman Unauthorized: Vigilantes, Jokers, and Heroes in Gotham City (2008), edited by comic book writer Dennis O'Neil.

Podcasts. While a number of other podcasts analyze the psychology of nerdy topics, this one is specifically about superhero stories.

• The Arkham Sessions, by Andrea Letamendi & Brian Ward.

The Arkham Sessions almost (though not quite) exclusively looks at Batman: The Animated Series. 
This next one, though not specific to superheroes, still includes much discussion about comic books and other sorts of fantastic heroes.

• Geek Therapy, founded by Josué Cardona and Lara Taylor Kester.

Blogs. Likewise, there are numerous blogs on the psychology of nerdy topics. These are specifically on the psychology of fantastic heroes and villains. Of the four, Dr. Letamendi's is probably the one most specifically focused on superhero stories.

• Beyond Heroes and Villains, by Travis Langley.
• Psychablog, by Robin Rosenberg.
• Superhero Therapy, by Janina Scarlet.
• Under the Mask, by Andrea Letamendi.

The blogs listed below are not as focused on superheroes but still include a lot of posts about superheroes and related characters.

• Comicspedia Blog, by Patrick O'Connor.
• Geek Therapy Blog, edited by Josué Cardona.
• Southeast Psych Presents, by the psychologists of Southeast Psych.

Vlogs. I do not yet know of a vlog (video log) by any psychologist whose videos look exclusively or even primarily at superheroes or supervillains.

• Sooner or later, I'll discover one worth listing here.

Database. This database catalogs comic book stories that can be helpful for therapeutic purposes.

• Comicspedia Database, founded by Patrick O'Connor.

Documentaries. The one documentary that explores the psychology of a specific superhero first aired as a special on the History Channel. The entire program is available on YouTube, but I suspect that's not an authorized copy. This documentary is very good. I didn't watch it for three years because I didn't want it to shape my thoughts while I was writing a book about Batman's psychology. I finally watched it very late in the writing process and got a few great quotes from it.

• Batman Unmasked: The Psychology of the Dark Knight (2008).

This one from DC and Warner includes interviews with two psychologists among all the actors, filmmakers, and comic book creators.

• Necessary Evil: Super-Villains of DC Comics (2013).

YouTube Videos. I seriously disagree with some of the YouTubers who talk about the psychology of superheroes, and yet I feel it would be remiss of me not to point out that you can find a lot of YouTube videos on the subject. Judge them for yourselves. There are some good ones among them, too. Pay attention to which of these YouTubers actually have credentials in psychology or psychiatry, although I highly recommend judging them critically because at least one of the professionals gets DSM criteria wrong and really does not understand Batman.
Listing my own works above bugs me, but the plain fact is that people who contact me to ask for this information already know something about my involvement with this topic anyway.
Writers who find these resources useful might also benefit from Andrew Lesk's bibliography of psychologists and psychiatrists appearing as characters in comic books and graphic novels. Andrew previously allowed me to share that bibliography here.