Superman
Batman
Flash
Green Lantern
Green Arrow
The Question.
Doom Patrol
Other.
Obvious answer is not listed: JSA
For a solo film, I'd go with Black Canary set in the 40s. Her solo adventures from that era are really one of the highpoints of the character's long career.
I think pretty much any DC franchise/character that's rooted or debuted during an older era could serve as a period piece.
I think a lot of them could work as period pieces. A Green Arrow film set in the late 1960s just makes sense since that was the time when Green Arrow came into his socially-conscious liberal persona. Another one that I'd like to see would be is a Question film set in the 1980s. Though, if we're still trying to at least achieve some semblance of an interconnected continuity, the latter would probably be a better route than the former, since Ollie is an iconic member of the League. Plus, if they set Question during the 80s, they can always show Renee Montoya taking over for Vic Sage in the present-day DCEU.
The JSA, but would love to see Justice League New Frontier!
Batman and Superman films set in the late 1930s/1940s would be great. Burton's Batman films already did that sort of, it was an ambigious time period that was a fusion of the 80s and the 40s. So that aesthetic fits Batman very well, and I'd love to see a film with an Anton Furst-inspired Gotham but straight up set in 1939. Most of his major characters and villains can function as is pretty well there.
Superman would be similarly great. We wouldn't have to worry about his occupation being outdated lol. And I'd love the kinetic, rough and tumble energy of the early Superman stories on the big screen, along with some later additions like Supergirl, Brainiac, Bizarro, Krypto, etc.
As much as I love Wonder Woman as is and think using WWI was a valid choice, I'd prefer a WWII era film for her as well. I want to see Paula von Gunther and the Holliday Girls.
Of the characters named on the OP's list, a Superman period piece interests me the most. Ditto with Batman.
But there are a bunch of other characters I'd specifically love to see in period pieces.
-I'd love a Power Girl film set in the mid-1970's. The film begins with her landing on earth, but in this version, there's no Superman to find her. She's got only vague memories of Krypton and her true origins. She has limited powers, akin to the Siegal/Shuster Superman. The movie is about her establishing a new life on earth as 'Karen Starr' even as she starts to use her powers as a costumed vigilante. Superman and the other heroes of the JSA are 'mystery men' in this reality, legends of a bygone era who have grown into urban myths, and Karen does start to ponder her possible connection to any of those disappeared heroes, especially Superman. But by and large, this is a film that revolves around Power Girl and the impact she has on the world of 1970's New York City.
-I'd like a Martian Manhunter film set in the late 50's, amidst the height of Cold War era paranoia and tensions. It'd be about him foiling an invasion by covert White Martian operatives.
-A Hawkman and/or Hawkgirl film could work in any era owing to the reincarnation.
The upcoming GL series on HBO Max will apparently be set across multiple decades and tell the origin stories of two Green Lanterns. I kinda hope they tell Hal Jordan's story during the early 60's. I wouldn't mind them updating John Stewart into a Gulf War veteran.
Oh yeah, as others have said, the JSA is an obvious choice for a period piece set in the 1940s or maybe even in the 1950s if you want to focus on the post-WWII lives of the JSA. That would be incredibly interesting, seeing them struggling with public opinion turning against them 10 years out from the war and with Senate commissions about their impact on society, sort of like an analogue to the real-world Senate hearings on comics books that took place in the 50s.
There are so many great ideas on this thread that the conclusion is obvious; WB----make it so! Make these movies!
JSA (40s)
Sandman (ala Mystery Theatre) (40s)
Black Canary (70s)
Madame Xanadu, Vandal Savage, Gentleman Ghost, Solomon Grundy, Clayface I, Baron Winters, Nathaniel Dusk, Andrew Bennett, the Question, Rose & Thorn (Victorian 1880s)
Zatanna and Zatara (1920s)
"There's magic in the sound of analog audio." - CNET.
You know I want to say JSA, but as it’s been said it’s the obvious answer. So I want to argue for some less obvious answers.
First, I’m gonna say the Freedom Fighters. I imagine you could either have them as the American and Allies team vs the nazis in world war 2 or you go the alternate history route where they are the last heroes of a world ruled by the nazi’s who won WW2.
Second, I’d argue Sgt. Rock. I’d imagine that he is one of the more well known DC military characters. I’m sure there is a lot there that could be pulled from.
Third if you want to go a more medieval route go with the Demon Knights, that was one of the better runs of the beginning of the new 52 and the medieval adventures of Etrigan could be cool.
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Words to live by.