When thinking about "realistic" comic books, the first and most defining factor has to be whether the comic book includes "superheroes" or not. I'm not necessarily talking about superpowers either - there's not much realistic about Batman in many of his incarnations, for example.
Comic books are not restricted to telling stories about superheroes. There are crime books, western books, "slice of life" emotional dramas, etc. etc. To my shame, this isn't a part of the comic book world I know a huge amount about.
Realism, quite frankly, isn't the job of the kind of comic book I enjoy the most.
But, when thinking about the best example of a realistic comic book the comic that springs to mind is something quite different, but something I think fits the brief. I'm talking about The Punisher Armory.
The Punisher Armory stretches the definition of a comic book. Yes, it's a combination of pictures and words, but this isn't a sequential narrative. It's a series of pictures, quite brilliant pictures in my view, accompanied by technical descriptions of the Punisher's various weapons (mostly guns, but not exclusively) and his personal opinions on them. I remember reading and re-reading these over and over again, there was something utterly fascinating about the way in which the technical details were mixed in with the Punisher's own psychology and story. It's a great example of how you can create engaging prose out of anything, if you work at it.
Why The Punisher Armory is genius in one page and one picture..
This gun isn’t a very good gun.
This gun shoots no known caliber, barely has sights and doesn’t even shoot what it does shoot very well.
It’s no ‘wonder nine’, accepts no scope of any kind; has no accessories for that matter, unless you count the ratty, vinyl-like holster that came with it.
It certainly isn’t gun-metal tough ; I probably could shatter it with my bare hands. It most likely would rust, if I let it. But it’s my most important gun.
When it saw its heaviest duty, it was the best gun there was. It could slide from that low-slung holster like a natural thought. It fired fifty, well-placed rounds squarely into the bad guys, whether they were gangsters or Indians or just young buddies up the block.
This was my little boy’s gun. Now I hold onto it and now and then, use it.
According to Comic Vine, The Punisher Armory was written by Don Daley. That may not be a name you're immediately familiar with, but I'd suggest you check out his work. The man knows his characterisation... and his guns.
I was really disappointed to discover that there isn't a trade paperback of The Punisher Armory. There's not even a Kindle or Comixology version. Looks like it's off to eBay for me, as I have no idea where my old copies are and I really, really want to read it again.
In the meantime, I've compiled a small gallery of pages from The Punisher Armory that I've scrapped up from the internet. (Thanks Google Image Search!)