There are tons of Matt Reeves, to go ahead and adapt.
While it seems from the trailer that The Riddler opposite Batman, but it could be kickstarting a franchise, so let's look at some hits they could use.
Year One
Robert Pattinson looks much younger than any of the previous Batmen, making it a pretty good possibility that we might see a movie adaptation of the Year One storyline. Functioning as a prequel, this storyline shows us what Batman's life was like when he first decided to don the Batsuit and become The Dark Knight.
We could also see this fitting the vibe since it's written by Frank Miller, who usually portrays Batman as a big brute, capable of being gritty. The Riddler doesn't make an appearance just yet, but there's a hint towards The Joker. Interestingly, the story also features younger versions of Jim Gordon and Selina Kyle, living their lives before they became hallmarks in Batman's life.
The Long Halloween
The Long Halloween is also an incredibly important Batman storyline, despite the fact that it hasn't yet had a one-to-one adaptation in the films yet. Christopher Nolan featured a lot of subplots and elements lifted from this storyline, mostly the parts regarding our main villain in the story and his origins, Two-Face.
That being said, almost all of the villains have a pretty big role in The Long Halloween, which means that either for this film or in the future once this new franchise gets its footing, we could very well see a proper faithful adaptation.
Hush
Hush is an absolutely wonderful Batman storyline that has yet to make its way to the big screen, which is a problem. Hush introduces the titular villain, who quickly became a major antagonist due to how personal his connection with Bruce Wayne is. This beloved and critically acclaimed storyline got an animated adaptation that unfortunately condensed the story and even changed the final twist, much to the disdain of fans everywhere.
It can probably be assumed that with Batman being they don't want to take a risk on Hush since it doesn't really feature any of the villains we know and love. That being said, this new franchise is a great opportunity to showcase it.
Knightfall
With Robert Pattinson playing Batman in the new franchise, it isn't incredibly likely that we'll see Knightfall happen to such a fresh and young interpretation of the hero -- especially since he hasn't firmly established himself yet and there's always the possibility that we'll see another BatFleck scenario happen.
All of that aside, the crew behind the new franchise could do something very important with Knightfall and finally give it the attention that it deserves. Oh, and it would also be super cool to see the Bat get broken again, in a way that's more faithful to the comic.
Year 100
Year 100 isn't necessarily a comic that's received as much critical acclaim as most of the other entries on this list, but that doesn't mean it wouldn't be an incredible candidate for an adaptation. In fact, Year 100 is kind of in the direction that DC should consider taking.
It isn't like DC is averse to doing anything as gritty as Year 100, but maybe they've avoided it due to the fact that it isn't actually Bruce Wayne as Batman in this comic run. The story takes place a century into the future where someone takes up the cape and cowl to fight off the fascist government that's taken over America. The thing is, Batman has been all but forgotten by this time, leading people to question just who's underneath the mask.
Hi Diddle Riddle
With how serious and grimdark Batman has become in pretty much any film he's been in, it would be really interesting if they decided to take advantage of what's actually a pretty good Riddler storyline from the famously campy '60s series featuring Adam West.
Taking notes from this more lighthearted romp would introduce a really hip and fun ironic detachment from the source material, which might make The Batman come across as not just another rehash of what a lot of directors have tried and failed to do since the Christopher Nolan films came out.
Zero Year
The run on Zero Year that Scott Snyder did lasted for over a year, clocking in at thirteen months. Despite the fact that it was originally decided to be a part of the Zero Year story event that happened to help jumpstart the New 52 universe, it overstayed its welcome. Snyder decided that he had written too much to just cut it off during the time that DC had planned to finish the Zero Year event.
This one is definitely a Riddler story and not only that but it's also an origin story, making the perfect cocktail to be the source material for the new film. It also showcases the fact that The Riddler can be a serious threat to The Batman rather than just a quirky dork who likes riddles too much.
The Riddler
The Riddler was actually the introduction of the character in Detective Comics, and boy did they introduce him with a bang. The Riddler showcases his ability to create deathtraps for our dynamic duo, rather than just portraying him as an obnoxious nerd that wants to prove how much smarter than Batman he is.
He definitely is that one obnoxious nerd we all know but he's so much more. Paul Dano portraying him should be able to capture that. Since this is the introduction of The Riddler and it seems like the filmmakers went ahead and did a darker take on his story, this classic debut is definitely up there.
Dark Knight, Dark City
It only makes sense that the creator of Hellboy, Mike Mignola, would have had something to do with Dark Knight, Dark City. While he did only do the cover art technically, it's pretty obvious that the writer and artists were influenced by his style and story.
This comic gets into the occult origins for a lot of Gotham's villains, beginning with the summoning of a demon. Aside from that, this comic run is one of the first depictions of The Riddler that frames him as being anywhere near as awful and sadistic as a lot of his contemporaries rather than the goofy nuisance he tends to be written as.
E. Nigma, Consulting Detective
While this arc most likely wouldn't happen until a Joker had been established in the new franchise, it definitely makes sense since The Riddler plays a major role in the film.
This was actually a Justice League Action episode, but it's noteworthy for its particularly interesting depiction of The Riddler. Here, he's forced by the Justice League to comply with them since he's the only person they know who's smart enough to figure out how the horrifically insane Joker's brain works. Specifically, they need him to figure out where the Clown Prince of Crime locked the Dark Knight up.
