Fan casting is a fun business. It keeps the community of any franchise thriving and gives the audiences something to talk about while we wait for official news from the studios. Interestingly, studio heads do pay close attention to this sort of thing and turn a watchful eye and ear to what the fans are saying. While it isn't always possible to get the actors we want because of scheduling conflicts, creative differences and contractual disputes, they take note of the reactions and keep it all in mind when trying to put together these massive projects. The superhero movie genre, in particular, has a vocal fanbase with tons of suggestions about who should portray which character and why. Some of the picks are mind-blowingly good and you can foresee a fruitful future in movie casting for a plethora of these passionate fans.

The likes of Bosslogic make many of these dream castings come to life by putting together some mock images and sending the internet into giddy delirium. Sadly, most of these fan castings never make it past the phase of online chatter – no matter how much we hope and pray for them to come true. For others, there's still a glimmer of hope until we receive confirmation of otherwise. So, we've looked up 20 of the best rumored superhero fan castings that we've heard and which we think are still possible. Sure, some of these might be dispelled in the next few weeks or months, but fans can still dream, right?

20 MATT DAMON (TWO-FACE)

While Affleck is still Batman, there's a chance that his BFF, Matt Damon, might make an appearance in a DC film. Sure, he's a little bit too old to portray Robin now, but there's sure to be a meaty part (or two) for Damon to sink his teeth into. As some fans have suggested, he might be just perfect for Harvey Dent/Two-Face.

Interestingly, Damon was actually up for the role in Christopher Nolan's The Dark Knight. He told MTV News the story: "I couldn't – there was a scheduling thing. I never spoke to Chris Nolan. I'm a big Chris Nolan fan, but I never spoke to him." Maybe now's the right time?

19 JESSICA CHASTAIN (POISON IVY)

Jessica Chastain as Melissa Lewis in The Martian

Perhaps the reason that Poison Ivy hasn't been explored in film lately is due to the negative reception of 1997's Batman & Robin. Still, this is likely to change if either Gotham City Sirens or Birds of Prey go into production, as Ivy is rumored to be a part of both scripts.

To play a nuanced villain like Ivy, there's a need for an actress who's capable of conveying both the good and bad of Ivy's psyche. Hence the fan outcry for Jessica Chastain. While she's currently working on X-Men: Dark Phoenix in an unspecified role, it's likely a one-and-done deal, so there should be no problem for Chastain to jump ship afterwards.

18 LEWIS TAN (NIGHTWING)

Lewis Tan Into the Badlands

After Chris McKay was confirmed as the director for Nightwing, many fans wondered who'd be cast as Dick Grayson/Nightwing. Several names have been suggested, but one of the more popular ones was of Lewis Tan, who is known for his work on Into the Badlands and Iron Fist.

Tan himself confirmed he'd spoken to DC recently about a few things, leading many to believe it was about Nightwing. Tan only added fuel to the fire after he chatted to That Hashtag Show about his meeting with DC. "There were a lot of different talks and Nightwing was one of those that were mentioned, so we'll see."

17 JON HAMM (BATMAN)

Jon Hamm

With the rumors swirling around that Ben Affleck is done with the role of Batman, everyone and their mother has been linked with the part. First, it was Jake Gyllenhaal – but he seems out of the picture now since he's been cast as Mysterio in Spider-Man: Far From Home. Then Jon Hamm's name was mentioned as a possible candidate for Matt Reeves' The Batman.

While the intel states that Reeves wants a younger star to play the Caped Crusader, the older Dark Knight has been warmly received by most DC fans. Let's face it: Hamm is a terrific actor, with the necessary look and feel to pull off the dual role of Bruce Wayne and his crime-fighting counterpart.

16 DOMINIC WEST (NORMAN OSBORN)

Dominic West

When you consider the live-action versions of Norman Osborn we've seen, we've really been spoiled with the likes of Willem Dafoe and Chris Cooper. Since Spider-Man has been rebooted once again, chances are we'll see a new Osborn soon. The question is, who's brave enough to follow Dafoe and Cooper?

The answer is Dominic West. The actor is no stranger to the superhero film genre, having portrayed Billy Russo/Jigsaw in Punisher: War Zone and has the required acting chops to play the ruthless and conniving Osborn. If there's someone who can make us despise the despicable character, it's West – and he'd put on a heck of a show as the Green Goblin, too.

15 JANE LEVY (BATGIRL)

Jane Levy

It seems like Barbara Gordon/Batgirl will be making her bow in the DC film universe soon. The character could make her debut in Birds of Prey or a standalone picture. One thing that fans have been adamant about is that a natural redhead should portray Gordon.

The most-celebrated fan casting for the part? Jane Levy. There have been some mock-ups made of what she could look like as Batgirl and the actress herself has confirmed her interest too. On her Twitter account, Levy joked: "Y'all keep [asking] if I am gonna play [Batgirl] and I think it's probably a good idea because I can do a lot of [push-ups]."

14 EIZA GONZALEZ (CATWOMAN)

Eiza Gonzalez in Baby Driver

As the comic-book world gets over itself and the Batman #50 controversy, it's important to realize that Selina Kyle/Catwoman will always be a fundamental part of DC Comics. The femme fatale has a lot of history but hasn't appeared in any live-action Batman films since Michelle Pfieffer's purr-fect performance in 1992's Batman Returns.

The DC film universe is rapidly expanding and it's only a matter of time before Cat makes her debut. After her performance as the outlaw Darling in Baby Driver (alongside Hamm, who's rumored to be the next Dark Knight), Eiza González has been a hot pick to take the part of Batman's favorite cat burglar. We can't help but agree with this casting suggestion.

13 DAN STEVENS (REVERSE FLASH)

Legion Dan Stevens

With The Flash film finally in development after years in the wilderness, the question is, who'll be the main rogue? The natural choice is the Reverse-Flash, since he's the Joker to Barry Allen's Batman. We've seen the character on The CW's The Flash, as portrayed by Matt Letscher, but a new actor will need to take the reins for the cinematic universe.

British actor Dan Stevens is a popular choice among fans to play Eobard Thawne. His portrayal of David Haller in Legion only adds extra credence to his ability to play multidimensional characters. Additionally, his ongoing role on Legion shouldn't be too problematic, since it isn't connected to any universe.

12 COLIN FARRELL (JOHN CONSTANTINE)

Colin Farrell in Fantastic Beasts and Where to Find them

Let's be honest here: Colin Farrell's Bullseye in 2003's Daredevil was pure gold. The Irish actor might've avoided superhero properties since then, but his portrayal as the villain was so hammy and over the top that it became so good. For years, everyone has wanted Farrell to return to another comic-book adventure.

The role that makes the most sense for Farrell is John Constantine. As the chain-smoking, snarky antihero, Constantine is literally the superhero version of the real-life Farrell. While it's unlikely that Constantine will get his own film, there are rumors that a Justice League Dark movie could be in development and the magic-conjuring Brit will be a big part of it.

11 HOLT McCALLANY (SANDMAN)

Holt McCallany in Mindhunter

Spider-Man 3 might've been one of the worst Spidey films ever made, but Thomas Haden Church's turn as Flint Marko/Sandman was a highlight. As a result, there's a demand to see the character return in a better film, which will allow for a deeper understanding of the conflicted villain.

After witnessing his mesmerizing performance as Bill Tench on Mindhunter, there are many who believe Holt McCallany is the right actor to play Sandman in a future project. McCallany has a history with superhero films, having appeared in Justice League as the no-name burglar who gets used as parademon-bait by Batman, but he deserves a much bigger role worthy of his talents.

10 RAY LIOTTA (HAMMERHEAD)

Ray Liotta

As the MCU goes deeper into its lore, we'll undoubtedly see a lot more fan-favorite B-grade villains appear in future films. Spider-Man, in particular, has one of the best rogues' gallery around and we foresee many of his foes making the leap to the big screen. Enemies, such as Hammerhead, could be popping up real soon.

Ray Liotta's stock has fallen in recent years, but we'll never forget his performance as Henry Hill in Goodfellas. It's this incredible, star-making turn that has convinced fans that he should play the two-bit crook Hammerhead in the MCU. Can you imagine the quips between him and Tom Holland's Spidey? Pure magic!

9 JOHN KRASINSKI (MR. FANTASTIC)

John Krasinski in A Quiet Place

There's an air of greatness around John Krasinski right now. The Office star is picking up terrific momentum in Hollywood and there's a sense that he's the next big A-lister. As expected, his name will be attached to superhero roles when they become available.

The latest speculation is that he could be the MCU's Reed Richards/Mister Fantastic when Disney finally gets the Fantastic Four rights. After his performance as Lee Abbott in A Quiet Place, there's definitely a sense that his portrayal there could serve as inspiration for him to play Marvel's sharp-minded scientist. Heck, why not include Krasinski's real-life wife, Emily Blunt, as Sue Richards/Invisible Woman while we're at it?

8 JEFF BRIDGES (DARKSEID)

Release the Snyder Cut! Well, we don't think we'd see much of Darkseid in that any way, but fans have every right to feel aggrieved about not seeing the intergalactic baddie in Justice League. There's a sense that it was a missed opportunity to showcase DC's biggest threat, but it's still possible that Darkseid will appear at some point in the future.

Hopefully, Warner Bros. has learned from its Steppenwolf mistake and won't rely purely on CGI to make its villains come to life and will also listen to the fans about who should play Darkseid. The indomitable Jeff Bridges is the only choice here, as he's more than adept at switching from calm and cool to beast mode in a matter of seconds.

7 JOEL EDGERTON (BLACK MASK)

There was a time when David Ayer was involved in the production of Gotham City Sirens – and he teased the likelihood of Black Mask being the big bad of the movie. However, with DC films mostly in a state of limbo while the new leadership figures everything out, it doesn't look like Ayer will be involved, nor will the film be fast tracked.

This hasn't stopped fans from selecting their pick for Black Mask. The name that keeps popping up is Joel Edgerton. Knowing what we do about Edgerton and his choice of roles, we wouldn't put this one in the not-happening category. It's entirely plausible that he'd be up for playing the loud-mouthed crime boss.

6 JOHN BOYEGA (BLADE)

star-wars-last-jedi-boyega

While most of us recognize Wesley Snipes as Blade, there will come a time when someone else will portray the legendary vampire hunter. It might be sooner rather than later, as the MCU expands its world and includes newer heroes and villains.

As the topic over who should play Blade heats up, John Boyega's name was thrown into the mix by quite a few fans. Boyega himself has said that he wouldn't take the part because he only sees Snipes as Blade – but we all know that money talks and actors love the green. The question is, does Boyega want to join another franchise with equally rabid fans as the Star Wars trolls?

5 BRIAN TEE (NAMOR)

Brian Tee

The MCU is in a bit of a complicated relationship with Namor the Sub-Mariner, as Kevin Feige revealed. Much like the Hulk, the rights are tied up at Universal and Marvel can't use the character. We're sure some discussions will happen, if Marvel wishes to use its own aqua-man in the future, so we wouldn't bet against Namor making an MCU bow down the line.

For many fans, the actor best suited to play Namor is Brian Tee. He is no stranger to comic-book movies, having played Noburo Mori in The Wolverine and the Shredder in Teenage Mutant Ninja Turtles: Out of the Shadows. Tee would be an inspired choice, with the required pedigree, for Namor.

4 MADS MIKKELSEN (DOCTOR DOOM)

Mads Mikkelsen in Hannibal

One of the more peculiar comic-book movies announced was Doctor Doom. Legion's Noah Hawley is writing the script and rumored to helm the director's chair as well. It's a rather strange prospect since you can't really imagine Victor Von Doom without the Fantastic Four involved, but it seems to be happening.

As soon as the news broke about the film, fans immediately pointed to Mads Mikkelsen as being the primary candidate to portray the Latverian villain. You only need to see Mikkelsen as Hannibal Lecter in the Hannibal TV series to see how he has the aptitude to portray a charismatic antagonist, who's downright evil but fascinating to watch.

3 CHARLIE HUNNAM (GREEN ARROW)

Look, as much as we love Arrow, we have to admit that it isn't really representative of DC canon. It's more like Batman-lite than anything else. Thus, it's about time that we get a proper Green Arrow property, which features a more true-to-form Oliver Queen.

Now, there's only one choice to portray Ollie: Charlie Hunnam, who looks exactly like the comic-book version of the hero. While Hunnam didn't show much interest in portraying the character initially, he's changed his tune over time. In an interview with Omeleteve last year, he said: " "Well then, c'mon, DC, what's up?! Gimme a call, I'm here!" Exactly. What are you waiting for, DC?

2 KATHERYN WINNICK (BLACK CANARY)

Katheryn Winnick

If we do get a Green Arrow film, then there's definitely an opportunity for Black Canary to feature as a primary character. Much like Hunnam is the only fan choice for Oliver Queen, Katheryn Winnick is the logical choice for Dinah Lance/Black Canary. There's so much artwork floating around the net of her as the character that you'd believe she'd been cast already.

Winnick hasn't been shy about admitting she'd take the part, either. In a tweet to a fan about the character, she said, "Been itching to try the Canary Cry... I got my own version." Will it happen, though? Well, it's up to DC and Warner Bros. now.

1 IDRIS ELBA (GREEN LANTERN)

Idris Elba as Luther

There's a lot of debate about who'll play John Stewart in Green Lantern Corps. We all know that Tyrese Gibson has eyed the role for years and tried to sell himself to Warner Bros. at every opportunity. However, his beef with Dwayne Johnson (Black Adam) may prove to be an obstacle, as we doubt that WB would want any further animosity in the DC film universe.

One name that's constantly mooted for the role is Idris Elba. Considering he's done with the part of Heimdall in the MCU, he's fair game for other superhero franchises now. After all, who wouldn't want to see Elba as the popular Green Lantern?