The U.S. Comic book industry used to publish several genres such as westerns, romance, war, crime, horror, fantasy, supernatural and sci-fi (that is not a licensed property like Star Wars or Star Trek).
Now the publishers are publishing mainly super hero comics and comics based on licensed properties such as GI Joe, Transformers, Aliens, Predator and Star Wars. Some indies including Archie Comics do currently publish non-superhero comics like teen humor. An indie tried to resuscitate some children's comics such as Casper the Friendly Ghost and Richie Rich but they flopped.
The Walking Dead is one of the best non-superhero comic books I have read.
I recall IDW is still licensing and publishing some Disney characters like Uncle Scrooge, Donald Duck and Chip N Dale's Rescue Rangers.
Why can't they make any successful non-superhero comic books today?
Recently I read some manga. I have discovered so many genres including Cooking genre in particular. I have read manga Chūka Ichiban! (Chinese cooking), Bambino (Italian food) and Yakitate!! Japan (bread baking).
I have discovered there is a lot of sports manga like Prince of Tennis and Slam Dunk (a basketball manga). They also have manga about baseball, boxing, soccer and volleyball, etc
There are more Japanese romance manga than there are American superhero comics. Fantasy is a more common theme than romance in the Japanese manga. A sub-genre of the fantasy genre in manga is called Isekai. There are so many isekai manga you can find on the net.
I have found some magical girl manga like Corrector Yui, Sailor Moon and Card Captor Sakura far more interesting than Sabrina the Teenage Witch comics.
I have read another manga genre called survival games. Titles such as Darwin's Game, Real Account and Btooom
There are several manga about zombies, including the title Gakkou Gurashi.
There is even a manga about charcoal burning. The manga title is Sumiyaki Monogatari, which means Tales of a Charcoal Burner in Japanese.
You can even publish a manga about knitting and make it sell a bit in Japan.