It's been ten years since Jon Favreau's Iron Man came out and kick-started what is now known as the Marvel Cinematic Universe. Starring Robert Downey Jr. as the titular hero, Iron Man was met with wide critical acclaim and financial success. From that point on, the Marvel Cinematic Universe kept on growing and introducing new characters, culminating in the most ambitious and epic crossover to date Avengers: Infinity War. The follow-up to Infinity War is slated for a May 2019 release, which honestly seems too far away.

Over the course of ten years and nineteen movies, the Marvel Cinematic Universe has introduced a myriad of heroes, such as Iron Man, Star-Lord, Black Widow, Doctor Strange, Spider-Man, Scarlet Witch and so on and so forth. Some of these heroes were introduced in their own solo movies, while others got their debuts in team-up films such as Avengers or Guardians of the Galaxy. But, for each and every one of these heroes to make an appearance on the big screen, concept artist first need to draw up tons of possible looks for the character. Only one design ends up being used in the movie, while the rest go to the perpetual collection of unused concept art, like the designs you'll find bellow.

25 DOCTOR STRANGE (DOCTOR STRANGE)

Doctor Strange Andy Park

In 2016, Marvel broadened its cinematic universe with Doctor Strange -- a movie about a world-famous neurosurgeon Dr. Stephen Strange whose life was changed forever after a car accident robbed him of the use of his hands. Blowing all his money on traditional medicine only to realize it wouldn't be able to help him, Dr. Strange traveled to a mysterious enclave known as Kamar-Taj where he acquired magical powers and became sorcerer supreme. With the charming Benedict Cumberbatch in the leading role, the risky Doctor Strange did extremely well with the critics, the fans and at the box office.

And since Doctor Strange is not a conventional hero, his costume is a far cry from what most other MCU heroes are sporting. After all, there’s no reason for the Sorcerer Supreme to be wearing spandex. Benedict Cumberbatch is dressed in an Asian-influenced, layered, blue kimono tunic topped off with his red Cloak of Levitation -- which, apart from allowing Strange to levitate, appears to be sentient. Doctor Strange’s costume is incredibly detailed and looks mighty impressive. However, it almost looked significantly different. Andy Park shared this alternate design for Doctor Strange’s costume, which depicts a much sleeker tunic and a slightly different cloak. Perhaps we will get to see something similar in one of upcoming MCU movies.

24 IRON MAN BULLET ARMOR (IRON MAN 3)

Iron Man 3 Bullet Armor Josh Nizzi

Tony Stark clearly doesn’t know how to relax and unwind. Apparently, this guy spent all his spare time following the events of Avengers designing and building new Iron Man armors. So, by the time we catch up with him once again in Iron Man 3, Tony Stark had already created about 40 new Iron Man armors, which he then destroys at the end of the movie. But before they went kaboom, we got to see all kinds of cool armors, including Blue Steel, Bones, Gemini, Igor and much more. Naturally, not all concept designs for Iron Man armors made their way to the big screen. But, thanks to Josh Nizzi we still got to see these unused designs.

All of the Iron Man 3 armors we saw in the movie, as well as those we didn’t get to see, have a unique look and purpose. This one is titled the Iron Man Bullet Armor. Appropriate, don’t you think? The design is very smooth, shiny and rounded. It looks unique and cool -- there’s no doubt about it, but it also looks so very weird. Still, we’re not saying we wouldn’t like this armor to make an appearance in the MCU. Although, preferably, not in combat.

23 ROCKET RACCOON (GUARDIANS OF THE GALAXY)

Guardians of the Galaxy Rocket Raccoon Justin Sweet

The Guardians of the Galaxy are a weird bunch, but the weirdest two are definitely Rocket Raccoon and his best bud, Groot. Surprisingly, when the first Guardians of the Galaxy movie was released, the walking tree and the talking raccoon immediately became fan-favorites. This unusual duo was constantly hilarious, looked downright adorable and the fans loved them. But seeing some of the early Guardians of the Galaxy concept art made us realize just how different these two characters could have looked. And by different we mean worse -- way, way worse.

Concept artist Justin Sweet did one of the early takes on Rocket Raccoon and made the foul-mouthed raccoon look like a creature from a bad horror film. This Rocket looks old, chubby and, for lack of a better word, ugly. His hair looks longer and he’s got these weird braids hanging from his cheeks. But the really confusing part about this design is that it doesn’t look one bit like the comic book character. The Rocket Raccoon that we have in the MCU is far more comic book-accurate and adorable, and there’s absolutely nothing wrong with Rocket being adorable. On the contrary, precisely because his cute demeanor is in stark contrast with his bitingly sarcastic and cynical personality did Rocket become a fan-favorite.

22 THE WASP (ANT-MAN)

Ant-Man The Wasp Andy Park

Evangeline Lilly will soon be making her debut as the Wasp in Ant-Man and the Wasp. Lilly made her first appearance as Hope van Dyne in the first Ant-Man movie, at the end of which we got to see the Wasp suit her father had been saving for her. However, a different version of the Wasp did make a brief appearance in Ant-Man -- Hank Pym’s wife, Janet van Dyne. During a mission to disarm a Soviet ICBM en-route to the United States, Janet disabled her regulator allowing her to shrink small enough and enter the missile. The mission was deemed a success, but Janet was lost to the Quantum Realm. Actress Hayley Lovitt portrayed Janet in Ant-Man, while Michelle Pfeiffer will be playing an older version of Janet van Dyne in Ant-Man and the Wasp.

When Janet disappeared into the Quantum Realm she was wearing a red costume, similar to that of her husband. The costume was designed by the concept artist Andy Park, who shared a few alternate versions of the suit on his Instagram. According to Park, designing the Wasp’s costume was a fun task and judging by the diversity of these designs we’re inclined to believe him. What you see above is one of his early takes on the Wasp’s costume that was rejected.

21 VALKYRIE (THOR: RAGNAROK)

Thor Ragnarok Valkyrie Ryan Meinerding

Valkyrie was originally planned to make her MCU debut in Thor: The Dark World. However, since the movie already had a lot of characters, Marvel decided that introducing Valkyrie would be a bit too much. But Marvel did not abandon Valkyrie completely and in Thor: Ragnarok the fierce warrior finally made her big screen debut. We were introduced to Valkyrie, also known as Scrapper 142, when she found Thor on planet Sakaar and took him to the Grandmaster to become a contender in the Grandmaster's gladiator fights. When we first saw Valkyrie, she was wearing her black Scrapper armor, as opposed to the white Valkyrie armor she wears during the final fight of the movie.

Concept artist Ryan Meinerding was the first to take a stab at Valkyrie and what you see above is his concept design for the scrapper costume. Meinerding’s design has far more decorations than the costume we saw in the movie. Here, the blues are more prominent and vibrant. Another noticeable distinction is the face art, which in Meinerding’s design is more pronounced. And this Valkyrie sports the popular undercut hairstyle. Overall, she looks as awesome as ever. Although we loved Valkyrie's look in Thor: Ragnarok, we wouldn’t mind if this design had been chosen instead.

20 BABY GROOT (GUARDIANS OF THE GALAXY VOL. 2)

Guardians of the Galaxy Groot Josh Herman

Guardians of the Galaxy Vol. 2's opening scene has been hailed as the best opening scene in movie history. While we can’t say for sure it’s the best one in movie history, we are pretty comfortable with calling it the best MCU opening scene. After all, what could possibly be more epic than Baby Groot dancing around to the tune ELO’s "Mr. Blue Sky", while the rest of the Guardians fight a humongous space monster? We can't think of anything. And what could possibly be more adorable than Baby Groot? Definitely, nothing. Angsty teenage Groot we saw in Avengers: Infinity War was entertaining for sure, but Baby Groot will forever hold a special place in our hearts.

One of the reasons we all liked Baby Groot so much is his design. We're just gonna call it, Baby Groot is the most adorable creature in movie history -- absolutely everything about Baby Groot is too cute to handle. From the adorable puppy eyes to the way he moves. Everyone involved in the making of Baby Groot did a marvelous job. According to the concept artist Josh Herman, working on Baby Groot was super fun. When Marvel told him that Groot was going to be a toddler in Guardians of the Galaxy Vol. 2, he did a number of different concepts, using props to make Groot look more child-like. This earlier design looks cute, but the one that was used in the movie is even cuter.

19 ANT-MAN (ANT-MAN)

Ant-Man Andy Park

We are approaching the release of Ant-Man and the Wasp, which comes out July 6th and will sadly be the last MCU movie of 2018. Ant-Man and the Wasp is the sequel to the 2015 film Ant-Man, and it will feature the return of Paul Rudd as Ant-Man and Evangeline Lilly’s debut as the Wasp. Both heroes were unaccounted for in Avengers: Infinity War, with Ant-Man’s last MCU appearance being in Captain America: Civil War. In the meantime, Ant-Man’s gotten himself a cool new suit, but more on that later.

Speaking of superhero attire, concept artist Andy Park shared this vastly different early take on Ant-Man. Park posted the photo on his Twitter and commented, "Here's a more different take I did of the Ant-Man suit for the film. These were fun but I'm happy w/what they picked". We have to agree with Park on this one, because as much as we dig this design, we prefer the one that was used in the movie. Call us old fashioned but we like our Ant-Man with just a bit more red. Ant-Man’s newest outfit which we will get to see in Ant-Man and the Wasp seems to be upgraded with a new helmet and overall a more modern and sleek design.

18 SPIDER-MAN (SPIDER-MAN: HOMECOMING)

Spider-Man Homecoming Ryan Meinerding

In 2016, Spidey finally joined the Marvel Cinematic Universe in Captain America: Civil War. A year later, Tom Holland got to star in his first solo movie as Peter Parker, Spider-Man: Homecoming. Sporting the cool new suit Tony Stark gave him, the friendly neighborhood Spider-Man faced off against the Vulture. Peter got a bit in over his head, so daddy Stark had to intervene, which he wasn’t all too happy about. Wanting to teach Peter a valuable lesson, Tony took away his Spidey suit. Speaking of the amazing Spidey suit Holland wore in Spider-Man: Homecoming, it was designed by Ryan Meinerding and almost looked very different.

The concept artist shared a number of alternate concept designs for Spider-Man’s costume that feature a large spider symbol on Peter’s chest. Showcased above are three incredibly cool designs Meinerding created that were passed over. The middle one is a tad too dark for the MCU’s Spider-Man and wouldn’t really fit with the character and the atmosphere of the movie, so it doesn't surprise us that it didn't make the cut. However, the Iron Spider armor we saw at the end of Spider-Man: Homecoming and recently in Avengers: Infinity War does have a large spider symbol on the front and it looks amazing.

17 THOR (THOR: RAGNAROK)

Thor Ragnarok Andy Park

The 17th film in the MCU and the third film in the Thor trilogy is by far the best Thor movie. Directed by the brilliant Taika Waititi and written by Eric Pearson, Craig Kyle and Christopher Yost, the movie received highly positive reviews and grossed $853 million worldwide. Packed with awesome action sequences, set to a fantastic soundtrack and funnier than any other Marvel movie ever made, Thor: Ragnarok quickly became a fan-favorite. A point of contention among critics and fans alike is Thor’s new haircut. Director Taika Waititi wanted to give the God of Thunder a haircut to go with his gladiator attire, which caused a rift in the fandom.

While some loved Thor's new style, others seem to prefer the God of Thunder to sport his golden locks. Chris Hemsworth looks attractive either way, though we have to admit that we are partial towards Thor’s new look. Concept artist Andy Park shared an alternate gladiator concept design on his Twitter, which features Thor with even shorter hair and a much different gladiator costume. The buzzcut may be a bit much and the costume just a tad too bulky, so we’re glad this designed got passed over.

16 GROOT (GUARDIANS OF THE GALAXY)

Guardians of the Galaxy Groot Anthony Francisco

In Avengers: Infinity War, we got to see an angsty teenage Groot who spent all of his waken hours playing Arcade Defenders, while the rest of the Guardians acted like his parents. In Guardians of the Galaxy Vol. 2, we got to spend some time with the precious Baby Groot being cute and reckless, while the rest of the Guardians acted like his parents. But, when we were introduced to Groot in the first Guardians of the Galaxy film, he was an adult. The humanoid tree that only ever said ‘I am Groot’ quickly became everyone’s favorite Guardian. Groot looked absolutely amazing, but it took some trial and error to get to the final design.

One of the early concept designs has Groot looking very menacing and kind of deformed, while the one you see above paints a cute, albeit stranger picture of Groot. This design was done by concept artist Anthony Francisco and looks rather interesting. Still, due to all these branches that stick out at odd angles and the blooming flowers covering Groot’s chest, forearms and shoulders, Groot looks more like a tree and less like a humanoid tree-like alien species. However, when it comes to adorableness, this Groot might be even cuter than the movie version.

15 MANTIS (GUARDIANS OF THE GALAXY VOL. 2)

Guardians of the Galaxy Vol. 2 Mantis Andy Park

Guardians of the Galaxy Vol. 2 introduced us to a number of new characters including Ego the Living Planet and Mantis. The empathic insect-like humanoid Mantis doesn’t share much with her comic book counterpart, something fans of the comic book character found disconcerting. Unlike in the comics, Mantis is of alien origin in the Marvel Cinematic Universe, which James Gunn announced prior to the movie’s release. Gunn stated in the past that Peter Quill will be the only Earthling member of the Guardians of the Galaxy, which is why Mantis’ origin story was changed. When it comes to the way Mantis looks, concept artists did a number of different designs that were supposed to reflect Mantis’ alien insectoid origin while making her look appealing to the human eye.

It’s safe to say that the final design was a success, especially with the talented and gorgeous Pom Klementieff as Mantis. Concept artist Andy Park played with a few different designs for the lovable Mantis. The design featured above is defined by the remarkable segmentation effect on Mantis' skin. According to Park’s Instagram post, designing the right look for Mantis was a fun process as he tried to balance the insect influence with an attractive look.

14 BLACK PANTHER (CAPTAIN AMERICA: CIVIL WAR)

Black Panther Captain America Civil War Jerad Marantz

Captain America: Civil War was an ambitious movie all around. Even though, it is technically the third instalment in the Captain America trilogy, Civil War juggled a large ensemble cast and felt more like an Avengers film. On top of that, the movie introduced new characters into the MCU, like Black Panther and Spider-Man. Luckily, the Russo Brothers were up to the challenge and did an impressive job, as did the cast. Portrayed by the amazing Chadwick Boseman, Black Panther stole the show. The fans loved everything about the character and pretty much everyone was praising the excellent costume design. However, there was a considerably different design in play back in the early stages of concept design for Black Panther.

This more organic design highlights the muscular structure and resembles the nanosuit from the Crysis video game. The muscle structure suit makes Black Panther look too menacing, which would be more appropriate if he was a villain. The design that ended up being used in the movie is far more suitable, comic book-accurate and aesthetically pleasing. The design was done by the concept artist Jerad Marantz, who also did concept art for DCEU’s Batman, as well as a very different early take on Ego the Living Planet.

13 FALCON (CAPTAIN AMERICA: THE WINTER SOLDIER)

Captain America The Winter Soldier Falcon Josh Nizzi

At the beginning of Captain America: The Winter Soldier we find Steve Rogers living a quite life in Washington D.C., two years after the Battle of New York. Struggling to come to grips with the 21st century and adjust to the modern society, Captain America becomes an Agent of S.H.I.E.L.D. and a close friend of Black Widow. Steve also makes a new friend, Sam Wilson, also known as Falcon. Cap’s relatively peaceful life gets turned upside-down when his believed-to-be-dead best friend Bucky Barns reveals himself as a brainwashed Hydra operative who goes by Winter Soldier. Relying on his new friends, Steve goes above and beyond to save his old friend.

Captain America: The Winter Soldier introduced us to a new MCU hero -- the Falcon. Portrayed by Anthony Mackie, Falcon is a former pararescue airman who uses a winged jetpack to soar the skies. Falcon’s wings are decorated with strokes of red, probably to pay homage to the character’s more flamboyant comic book costume. Josh Nizzi who created concept designs for Falcon shared alternate designs, including the one you see above. Falcon almost looked more bird-like, but there are also designs that make him look more like a plane. Ultimately, Marvel settled for something in between.

12 QUICKSILVER (AVENGERS: AGE OF ULTRON)

Avengers Age of Ultron Quicksilver Jack Dudman

The year 2014 was the year of Quicksilver. In April, we caught a glimpse of Pietro Maximoff, played by Aaron Taylor-Johnson, being held captured by Wolfgang von Strucker in the mid-credits scene of Captain America: The Winter Soldier. In May, Johnson’s Kick-Ass co-star, Evan Peters made his debut as Quicksilver in X-Men: Days of Future Past. Although, it wasn’t until Avengers: Age of Ultorn that we got to see the MCU Quicksilver in costume. Both the X-Men and the MCU versions differed considerably from their comic book counterpart. Aaron Taylor-Johnson’s Quicksilver costume is regarded by many fans as the worst MCU costume to date.

Although, not entirely inaccurate, the costume was too bland and looked like something from Under Armour. Concept artists who worked on Avengers: Age of Ultron shared a number of different concept designs they did for Quicksilver. Some of those scrapped designs would have made Quicksilver look way better. However, the vast majority of the concept designs we found are even more outlandish than the one that was used in the movie. But, perhaps the least costumey Quicksilver costumes were designed by Jack Dudman. Dudman made a few of these unusual Quicksilver concept designs, but the one shown above takes the cake.

11 HAWKEYE (CAPTAIN AMERICA: CIVIL WAR)

Captain America Civil War Hawkeye Andy Park

Poor Hawkeye has been severely neglected by the MCU. Ever since his first appearance, the fans have been talking about how underused he is. As a result, Hawkeye looks useless when he really shouldn’t. Sadly, Hawkeye kind of became the butt of the joke. So far, he's appeared in four MCU movies -- Thor, The Avengers, Avengers: Age of Ultron and Captain America: Civil War -- and in all of these movies he’s sported a different costume. Hawkeye’s look was perhaps at its best in Captain America: Civil War, but it could have been even better.

Concept artist Andy Park shared some alternate designs for Hawkeye’s costume, which includes a version with a face mask and red goggles. Unfortunately, Marvel passed over this amazing design. But, given that Hawkeye became an outlaw by joining Cap’s team it would have made sense for him to use a mask to hide his identity. The archer was suspiciously absent from Avengers: Infinity War, leaving fans wondering what he’s up to. A popular theory that picked up steam after a couple of set photos from Avengers 4 made it online, is that Hawkeye will become Ronin in the upcoming Avengers sequel. We'll see if this pans out in May 2019.

10 HULK (THOR: RAGNAROK)

Thor Ragnarok Hulk Ryan Meinerding

Thor: Ragnarok borrowed quite a lot from the "Planet Hulk" storyline, so unsurprisingly the big green guy plays an important role in the film. When Thor arrives on the planet Sakaar he is forced to become a gladiator and face off against the Grandmaster’s champion, which coincidentally happens to be his friend from work, the Hulk. Not knowing that the Hulk has been in control since the events of Avengers: Age of Ultron, Thor attempts to reason with his opponent, which doesn’t work out well for Thor. Eventually, Thor finds a way to get through to Banner and set him free from the prison of his own making.

The years Banner spent with the green guy at the wheel have definitely taken a heavy toll on him, which was visible throughout Thor: Ragnarok as well as Avengers: Infinity War. While creating possible concept designs for the Hulk, Ryan Meinerding got very creative with Hulk’s hairstyle. Meinerding shared four different designs for Hulk’s haircut, but the one that stands out the most is the Hulk with long hair and a beard. It’s kind of surprising they didn’t go with this one since it would fit perfectly with his storyline and it would work as a good juxtaposition with Thor’s new short hair.

9 NOVA CORPS (GUARDIANS OF THE GALAXY)

Guardians of the Galaxy Nova Corps Anthony Francisco

The planet Xandar and the Nova Corps played a big role in Guardians of the Galaxy. The first time Star-Lord, Gamora, Rocket Raccoon and Groot meet was on Xandar, and after failing to sell the Orb, Quill is ambushed by Gamora, who steals the Orb. Star-Lord chases after her and they fight over the MacGuffin. Gamora then tries to kill Quill, but she’s stopped by Rocket Raccoon, who then instructs Groot to bag Quill, aka their booty. The situation escalates and the group is soon arrested by the Nova Corps and transported to the Kyln, which is where they meet the last member of Guardians of the Galaxy -- Drax.

The Nova Corps appears a few more times throughout the movie, including the final battle which takes place on Xandar. The designs for Nova Corps in Guardians of the Galaxy didn’t look bad, but they could have been better. The suits, especially the chest plates, work rather well. However, the problem most fans had with the Nova Corps design is the helmet, which didn’t really look like the Nova Corps we know from the comics. Concept artist Anthony Francisco had a different, more comic book-accurate, helmet in mind when he took a stab at Nova Corps.

8 WINTER SOLDIER (CAPTAIN AMERICA: THE WINTER SOLDIER)

Captain America The Winter Soldier Josh Nizzi

While James Buchanan "Bucky" Barnes was introduced in Captain America: The First Avenger, his alter-ego the Winter Soldier made his debut in Captain America: The Winter Soldier. The amazing Sebastian Stan reprised his role in the second Captain America movie and made audiences fall in love with him even more. Poor Cap finally understood what his fellow Avenger Thor had to deal with because his villainous brother Loki is more popular than him. Perhaps Cap and Thor could form a support group or something? But, we digress. Let’s get back to Winter Soldier.

Once again, Marvel managed to impress everyone with a spot-on comic book adaptation of an iconic character. Bucky’s prosthetic arm looks nothing short of remarkable, which goes for Bucky’s overall appearance. However, before they settled on the design that was ultimately used in the movie, Marvel considered a lot of different designs. Concept artist Josh Nizzi published multiple alternate concept designs for the Winter Soldiers. The one showcased above is the most drastically different one because of the mask. While the design is certainly not horrible, we have to say we prefer the one that was used in the movie. Still, it’s interesting to see all the different options that were on the table.

7 IRON MAN HULKBUSTER ARMOR (AVENGERS: AGE OF ULTRON)

Avengers Age of Ultron Iron Man Hulkbuster Josh Nizzi

Avengers: Age of Ultron is often cited as one of the lesser Marvel Cinematic Universe films. However, the importance of this movie should never be understated. After all, this is the movie that introduced Scarlet Witch, Quicksilver and Vision, set into motion the events of Captain America: Civil War, set up Thor: Ragnarok by sending Hulk into space, made the first actual reference to Wakanda and gave us the first hint that Thanos is coming to Earth. Oh yeah, and it gave us the freakin’ Hulkbuster armor. People really don’t give this movie enough credit.

Tony Stark’s Iron Man Mark XLIV armor, better known as the Hulkbuster, was created with the help of Bruce Banner with the sole purpose of restraining the Hulk. After Scarlet Witch drove Banner mad and caused him to turn into the Hulk, Stark had no other option but to call upon the Hulkbuster. It’s massive, powerful and stylish. And, if we’re being honest, one of our favorite Iron Man armors in the MCU. Seeing it back in action in Avengers: Infinity War and piloted by Bruce Banner made us very happy. However, the infamous Hulkbuster almost looked like a Transformer. Luckily, this design by Josh Nizzi was rejected.

6 SCARLET WITCH (CAPTAIN AMERICA: CIVIL WAR)

Captain America Civil War Scarlet Witch Andy Park

When Scarlet Witch appeared in Avengers: Age of Ultron she did not have much of a costume. Fans were disappointed to see such an iconic character running around in a black dress topped off with red leather jacket, while everyone else had a proper costume. Granted, she did appear in an actual costume for about two seconds at the end of Age of Ultron. Still, when time came for Elizabeth Olsen to suit up for Captain America: Civil War a new, and slightly improved, costume was designed. What you see above is one of the alternate design created by Andy Park, which we would have loved to have seen in the movie.

Scarlet Witch’s costume has had a few different iterations already, but neither has been amazing. The actress herself stated that she has a problem with how much cleavage she’s showing while all the other female heroes are covered up. She also mentioned the leotard and headband her comic book counterpart is famous for, stating that she’s at least glad the designers knew that’s not cool. For what it’s worth, we totally agree with you, Elizabeth. Hopefully, the day will come when a design similar to the one we see above will make its way to the big screen.