It really is amazing how much the superhero genre has exploded over the last quarter of a century. Before 2000, the only cinematic releases under the Marvel banner were for C-list characters. Meanwhile, the more well-known names at most had direct-to-video or TV movies. Now, as the Marvel Cinematic Universe is about to return from a year of (mostly) rest, we live in a world where there have been over 70 Marvel box office releases when you include all the other studio efforts. Its a lot.The House of Ideas has so many comics, with so many heroes and villains, but Marvel Studios is starting to reach the point where theyre running out of A-listers to pick out of a hat. We just had a movie with Knull in it, people. Knull! Were really scraping the bottom of the barrel, when there are still a few bigger characters yet to appear in the MCU.So, who hasnt shown up yet? Who are the bigger guns that Marvel and previous studios have been sitting on? Were counting the Marvel characters who havent appeared in either a theatrical release based on a Marvel comic or a TV show that is directly connected to the MCU. Just because Miles Morales has not appeared in live-action does not mean hell be included in the list.There will be a handful of choices that are borderline due to cut content, blink-and-youll-miss-it background appearances, and easter eggs. Those will be called out when we get to them.15. MorphWith over a dozen X-Men movies to their credit, 20th Century Fox was able to represent all the mutants who appeared in the 90s animated series but one. Granted, Morph was not on the show that much. Morph messed us up with their early death for shock value, came back as a brainwashed pawn, went through a lot of therapy, and only returned for good in the finale. In fact, Morph just recently got their full due thanks to a bigger role in X-Men 97 and a staple role in the Exiles comic series.Why Morph was absent from the movies is obvious. Those flicks went all-in on another shapeshifter: Mystique. But when its time for the MCU to do their own X-Men stuff, maybe they could differentiate their take by putting the spotlight on a different shapeshifting mutant.14. AresThe teaser for Hercules at the end of Thor: Love and Thunder is one of those cliffhangers that may never really get followed up on. But if we do get to see Brett Goldsteins portrayal as the Greek demigod again, theres a strong chance that well get to see his infinitely cooler brother, Ares. While not for a long stretch, there were a few years in the 2000s when Ares was a prominent antihero in Marvel, both as a member of Iron Mans Mighty Avengers and Norman Osborns Dark Avengers.Marvels Ares is a lot more in-your-face than what David Thewlis did with the God of War in DCs Wonder Woman. This Ares, described as a Thor and a Wolverine in one by Carol Danvers, is not only powerful and a genius tactician, but he also likes to get his hands dirty in the most extreme, metal ways. Like how he led a training exercise by firing a gatling gun with one hand and using the other to chug down a beer. The MCU could do worse than giving us a scene of Ares pouring blazing oil onto himself and then being catapulted into the center of the enemy army so he can go ham.13. Beta Ray BillIf Taika Waititi and James Gunn were less annoyed about Thor joining the Guardians of the Galaxy at the end of Avengers: Endgame, we might have actually seen good old Bill pop up. On one hand, that might have stepped on the toes of Thor: Love and Thunder being based around somebody else wielding Mjolnir, but Janes gone now, so theres always the chance the Korbinite warrior might one day pick up the enchanted hammer, not realizing what a big deal that truly is to pull off.Thors horse-faced alien counterpart at least exists in the MCU in some form, as his image appeared in Thor: Ragnarok as part of a Mount Rushmore of former champions in the Grandmasters colosseum. Its a fitting easter egg, as Beta Ray Bill had a supporting role in the Planet Hulk animated movie where he was also forced to face Hulk in a gladiator fight. Bills role in the MCU multiverse recently got a nod in What If? season 3, where he appears as a figure in the Exiles superhero-themed foosball table.12. TigraThere are basically two kinds of Avengers: popular solo superheroes with their own comics who got roped into this supergroup; and B-listers who are mainly remembered for crashing at Avengers Mansion for 10 years at a time. Its what separates Captain America from Vision. There are a handful of these latter types who still havent shown up in the MCU like Jocasta, Dr. Druid, Stingray, and so on. Wonder Man was the most prominent of this crew, but he has a Disney+ show coming up, so Tigra it is.Join our mailing listGet the best of Den of Geek delivered right to your inbox!The heroic werecat is a hard one to place as she wouldnt be high enough on the ladder to be on an Avengers team, and she would be a little too outlandish for Daredevils street-level buddies. Its probably why Hulu almost made a Tigra and Dazzler animated series. At least Tigra did get to have her slight moment in the sun when the animated incarnation from Avengers: United They Stand showed up as a comic convention regular in the Chip n Dale: Rescue Rangers Disney+ movie. She got to hang out with Ugly Sonic and his disturbing human teeth!11. DakenIt makes sense. When you do a movie that revolves around Logans secret daughter, its hard to find time and space for Logans secret son. Akihiro is a great character, both as a hero and a villain, but putting him in the MCU runs the risk of having too many Wolverine-type characters at once. Its a shame, as Daken has an interesting dynamic as the defiant son of the most defiant superhero. Hes the Marvel version of that Doug sketch from MTVs The State where a cool teenager is desperately trying to uphold a rebel image against his cigarette-smoking Hells Angel dad who produces albums for Bob Dylan.If Dafne Keen does ever end up being in another Marvel movie and takes up her fathers mantle, thats probably the best chance Daken has of showing up. Daken is a perfect foil as the tortured son of Wolverine who hates what he represents due to Logan never being there for him. Otherwise, turn him good and give us Hellverine, the Wolverine/Ghost Rider hybrid. A Hellverine movie would make a billion dollars on opening night.10. Omega RedOmega Red is one of those comic characters like Spawn whos like a 90s elemental. Once the decade ended, so did their power and presence. It wasnt until the nostalgia kicked in that Arkady Rossovich made a return to X-Men comics, and by that time, the Fox movies had long run their course. Thats not to say he was completely absent, as Omega Red was intended to have a cameo in Deadpool 2, but the only footage that didnt end up on the cutting room floor was him being blurry in the background. Were not counting that.But this other, other anti-Wolverine is ready for primetime. On the one hand, once the MCU has its own Wolverine, hes an easy, fresh villain to throw at him. On the other, they can also use him as a continuation of the Red Room and all that shady Russian government stuff. Maybe hes been on ice as a failsafe. Whatever the reason for his inclusion, the world needs to hear someone discuss his Mutant Death Factor powers while keeping a straight face.9. Squirrel GirlSquirrel Girls star has risen thanks to Marvel Rivals, and its really only a matter of time before we see Marvels greatest overachiever show up and give pet names to each of Thors abs. Maybe theyre saving her for the post-credits scene in Avengers: Doomsday where Nick Fury calls for help with a pager with a pixelated squirrel on it. Steve Ditkos greatest creation could pop up nearly anywhere and feel natural, so the question is not if but when.Having her on this list comes with a big asterisk. We came very close to an MCU Squirrel Girl played by Milana Vayntrub in New Warriors, a streaming show that unfortunately never made it past the pilot. Vayntrub still went on to voice the character in both Marvel Rising and Marvel Rivals. Then theres the not-quite-canon Disneyland ride Web Slingers: A Spider-Man Adventure, which deals with a group of smart youngsters called the Worldwide Engineering Brigade. This group not only includes Taylor Nicolette as a live-action Doreen Green (sans tail), but also Moon Girl of Devil Dinosaur fame!8. MojoGuys, when Channing Tatum gets that Gambit spinoff movie greenlit, were going to need to find a spot for Mojo. After all these years of outlandish superhero stuff in movies, the public is ready for a coked-up Jabba the Hutt TV producer with robot spider legs, but does that mean Marvel Studios head Kevin Feige should really do it? Would this just end up being MODOK 2.0? Mojo is for sure a major player in the X-Men mythos, but hes not somebody who gets that big of a spotlight. Hes a one-off bad guy for throwaway storylines and not somebody you base a huge arc around. Hes only good in small doses.Still, hes such a larger-than-life character who could be really fun in the right hands and would be a more entertaining choice than Arcade, who ultimately fulfills the same function as a villain mastermind. Besides we already know that he exists in the X-Mens movie universe, considering Shatterstar comes from Mojoworld, according to Deadpool 2. Make it trippy, throw in Longshot and Spiral, and you have a stew going.7. Rick JonesThis entry isnt a plea to incorporate Rick Jones into the MCU. If there was ever a time to include some version of Rick, that time had long passed. Its just kind of crazy to see him so absent considering what an important part of Marvel he used to be. In a time when Marvel writers felt that the Robin-type teen sidekick didnt fit the vibe, Rick was the outlier. The Hulks best friend and crux for his origin, an honorary member of the original Avengers, a protg to Captain America, and the Billy Batson to Mar-Vells Captain MarvI mean, Shazam. He was the Forrest Gump of 60s and 70s Marvel Comics!Weve had two Hulk movies but neither included Rick (though the nothing character Harper from Hulk does fulfill the role of getting shoved out of the way so Banner can get blasted with radiation). The closest was the video game adaptation of Incredible Hulk, which expanded on the movies story. Maybe if that World War Hulk movie ever happens, they could find a spot for him. His gamma alter-ego of A-Bomb could work, but then again, A-Bomb was a good guy version of Abomination. And these days, MCU Abomination is a pretty chill dude.6. FirestarIn the late 70s and early 80s, the rights to Human Torch were complicated by the desire to give him his own solo movie that never materialized. That meant the Fantastic Four cartoon had to use HERBIE, and Spider-Man and His Amazing Friends had to introduce new character Angelica Jones, otherwise known as Firestar, to team up with Iceman and the titular wallcrawler. This put her in the pantheon of comic book superheroes who first appeared in cartoon shows, alongside Harley Quinn, X-23, Reptil, Renee Montoya, and sure, HERBIE. He makes good sauce.While not the most standout character in Marvels repertoire, Firestars memorable time as an animated teammate to Spider-Man has led to her joining plenty of superhero teams over the years, being a founding member of the New Warriors, becoming an Avenger, being part of the X-Men, and so on. Just an easy character to throw wherever. Funny enough, a version of Firestar has already been part of the MCU, as Liz Allan (of Spider-Man: Homecoming fame) was Firestar in the Ultimate Marvel continuity instead of Angelica.5. MoonstoneThe Thunderbolts have taken many forms in the comics. Unfortunately, the iconic original version cant be used for the MCU due to Mysterio already playing the same card with his wolf in sheeps clothing scheme in Spider-Man: Far From Home. Even though most of the characters from the Thunderbolts movie have been part of various comic incarnations of the team, theres a shocking lack of the original crew. In fact, other than Baron Zemo and the rumors that Geraldine Viswanathan will be playing Songbird, none of the original Thunderbolts have yet to appear in any MCU project.The one who hovers above them all is Karla Sofen, otherwise known as Moonstone. This powerhouse is what Loki was before he became too likable: a conniving, manipulative, selfish backstabber. Shes motivated by survival, luxury, and getting the most with the least amount of work. Its this ambition that got her a spot as the governments official Ms. Marvel when Norman Osborn ran the Avengers. Ever since that run, people have been speculating that she could one day be a prime antagonist for Captain Marvel in the movies.4. HulklingSince the beginning of Phase 4, the movies and shows have been very adamant about building up this worlds version of the Young Avengers, including a scene of Ms. Marvel attempting to assemble the team. Were reaching the point where all of these youngsters are going to be in their 40s by the time we get to the big team-up, but theres still a little time. The Young Avengers comic only had two major runs, and nearly all the main members of the team have been represented in some way with a few exceptions.The biggest exception is Hulkling, a Kree/Skrull hybrid who used his shapeshifting to make himself look like a young Hulk. The thing is Skrulls arent exactly in-season with the MCU. The two-hit combo of Secret Invasion and The Marvels have killed interest in our green alien friends. Even if were getting more focus on Hulk-related stuff in the near future, we already have a young Hulk character in Skaar, introduced at the end of She-Hulk: Attorney at Law. Despite Hulklings boyfriend Wiccan getting the spotlight in Agatha All Along, this guy might be too complicated and ill-timed to fit into the bigger picture.3. Black CatOkay, okay, yes. This one is the most debatable. The Amazing Spider-Man 2 had Felicity Jones show up as a woman named Felicia for a few seconds of screentime as Harry Osborns assistant. Its a role nobody would remember if not for the fact that it was supposed to be Felicia Hardy, and her actress was way too famous for such a minor part. As Amazing Spider-Man 2 came out when Sony still saw dollar signs in the concept of a Spider-Man Cinematic Universe, the initial idea was to use this cameo as a first step toward a Black Cat/Silver Sable team-up film.Its just one of several close calls we had with live-action Black Cat. She was also in earlier scripts for Spider-Man 2 and was apparently planned for Spider-Man 4. Considering we have 10 Spider-Man movies and six quasi-Spider-Man movies on top of that at this point, seemingly every major part of the Spider-Man corner of Marvel has shown up onscreen except Black Cat (and the Jackal, who is at least an unseen plot point in Kraven the Hunter). Now that the Sonyverse is completely kaput, we might finally get to see her make a real appearance in the MCU proper.2. Mr. SinisterWe wereSo close. Mr. Sinister was what Foxs X-Men Cinematic Universe was building toward right before everything collapsed. The post-credits scene for X-Men: Apocalypse featured Wolverines DNA being taken away by Essex Corp. Deadpool 2 featured the Essex House for Mutant Rehabilitation, and New Mutants was intended to be one big backdoor to Sinister, rumored to be played by Jon Hamm. Then Disney bought everything and that died on the vine.There are a million X-Men characters out there, and half a million of those have not shown up in a movie. But Sinister is easily the biggest one among them. Hes the perfect threat for when the MCU starts messing with mutants, and considering his status as an obsessed geneticist, he could easily become the reason behind mutants popping up in an established universe that hasnt brought it up in all these years. Just make him the flamboyant bitch that he is in the comics and were good. The Marvel movies need a Dr. Frank-N-Furter to liven things up!1. AnnihilusThe big three final boss characters in Marvel are Thanos, Galactus, and Dr. Doom. Thanks to Fox having Fantastic Four movie rights, the MCU could only rely on Thanos for a long while and are only now able to play around with the other two. But then what? Try Apocalypse in this timeline? Turn Hulk into the Maestro? Give the Juggernaut scissors and see what happens when he runs around? Kang the Conqueror was a good idea at the time, but real life cut that off at the knees. No, the best play would be to bring Annihilus into the mix.The Living Death Who Walks is another Fantastic Four villain, but considering the Fox Fantastic Four movies could never get past adapting Doom and Galactus, those movies never got to Annihilus. The nice thing is that even with Annihilus being wrapped up in the Fantastic Four film rights for so many years, he isnt beholden to that specific property in the MCU. The Annihilation comic event showed what a universe-ending threat this cosmic locust really is with an entire Negative Zone full of monster bugs at his disposal. The guy had Thanos on the payroll and weaponized Galactus against his will. What more could you ask for in a new big bad?