Batman may have started his career as a costumed superhero alone, but the truth of the matter is that it wasn't long before he had a whole bunch of allies in his fight to protect Gotham City. While Bruce Wayne already had Alfred and Commissioner Gordon as allies, the Caped Crusader rapidly found a sidekick in Robin. But as the two became known as the Dynamic Duo, there was also a very important third ally and pillar of the Bat-family in Barbara Gordon's Batgirl. The character might have arrived much later in the game, but she has always proven to be one of the most important female additions to DC's pantheon of superheroes. In fact, like Batman and Robin, the Batgirl mantle proved to have a legacy of its own, with more than one character following in Barbara's footsteps.

Now, as the world of the DC Extended Universe of movies continues to expand, we are getting closer and closer to finally getting a live-action Batgirl movie. At one point, Joss Whedon was attached to direct the project, but the director ended up leaving the film. However, the movie reportedly remains in Warner Bros.' pipeline, with rumors that the studio is looking at an actress of Kristen Stewart's caliber to play Barbara Gordon. But what will Batgirl look like when she finally hits the big screen? Which costume will she be seen patrolling the Gotham City streets in? Will it be a costume that honors her original appearance, or will it be a much more modern take? Which, in the character's long history, has looked the best, and which has looked not as great?

19 BETTY KANE: BAT-GIRL

While Barbara Gordon is the most commonly known Batgirl, most people may not realize that she wasn't the first. In fact, the original Bat-Girl was Betty Kane, and she first appeared in 1961's Batman #139, with a costume that looks nothing like what Batgirl is usually associated with today.

In these original appearances, Betty's costume was mostly red and green, with a touch of black. She had the appropriate cape and bat-belt buckle, and no cowl – simply a domino mask. However, the rest of her outfit may not have been the most practical to fight in, given that it was mostly a dress. Later, the character would assume the identity of Flamebird.

18 BATMAN & ROBIN

In the much-maligned Batman & Robin movie, starring George Clooney as the vigilantedCaped Crusader, Batgirl would make her big screen debut. However, she wasn't Barbara Gordon. Instead, actress Alicia Silverstone played Barbara Wilson, the niece of Bruce's butler, Alfred Pennyworth.

In the film, Barbara would become Batman's second sidekick, taking to the streets of Gotham City with a costume that might best be left in the '90s. With a leather aesthetic, silver highlights and what looked like not much in the way of practicality, Barbara Wilson's first movie costume is definitely not one that should serve as inspiration for her solo film.

17 THE BATMAN

The Batman was a short-lived animated series that explored the adventures of the Dark Knight through a different, slightly more modern lens. The energetic cartoon presented its own spin on the Batman mythology, from the villains to the costumes. The series' version of Batgirl was equally different.

On the series, Barbara suited up as Batgirl in order to save her father from Poison Ivy. Her costume was almost entirely purple, with slight hints of yellow and black and, like Betty Kane, her look was mostly recognizable thanks to her dress-like outfit. The big white eyes, which were a signature of the series, completed the cowl.

16 INJUSTICE

Barbara Gordon was a playable character in the Injustice video game. The alternate world of the game was a much darker place where Superman ruled with an iron fist. Since hero fought against hero, armored costumes were the preferred and safer choice for most characters – and especially for Batgirl.

However, while the video game featured a Batgirl that had a protective suit comparable to Batman, it may not have actually been Barbara's best look. The large logo that stretched to the shoulders looked like something lifted from the Batman & Robin movie, and the cowl lacked the appropriate amount of menace to the Bat-silhouette.

15 ELSEWORLD'S FINEST

In Elseworld's Finest, readers were transported in an alternate reality where the classic duo of Batman and Superman were women, Supergirl and Batgirl. Supergirl's costume closely resembled that of Superman, with just a few alterations, and Batigrl's costume was effectively something that the Dark Knight would have worn.

The costume was entirely armored, and mostly black. With silver shoulder pads, gauntlets and utility belt and a large, flowing cape, this Batgirl was all Dark Knight. The only thing that called back to her older appearances was the yellow Bat-symbol. But make no mistake, this was Batgirl in name only – for all intents and purposes, she was the one and only Batman.

14 BATMAN '66

Barbara Gordon's Batgirl made her first comic book appearance in 1967's Detective Comics #359. She was created to appear simultaneously in the third season of the Adam West-starring Batman '66 television series. Played by actress Yvonne Craig, Batgirl made her live-action debut on the small screen, with a costume that would become iconic.

While her first comic book costume had her dressed in black and yellow, on the television series, Batgirl's costume first introduced the signature purple and yellow color scheme that would become a staple of the character's outfits throughout the years. Perhaps not the stealthiest of costumes, Barbara's shiny outfit made her stand out, and her bright colors communicated that she was as colorful and energetic as the series’ dynamic duo.

13 BOMBSHELLS

The DC Bombshells universe is a reality set in the 1940s, and it showcases all of the publisher's most famous female characters. From Wonder Woman and Harley Quinn to Supergirl, every character received a costume overhaul so that they might look like they were lifted from classic pin-up arwork.

In this alternate reality, Barbara Gourdon is a French pilot whose costume, appropriately, resembles a sort of nostalgic aviator ideal. The character's look is made whole thanks to her goggles and scarf, while the rest is classic Batgirl, with the use of purple and yellow. However, to honor the aesthetic of the era and of the series, hers is a much more revealing outfit than usual.

12 WHITE KNIGHT

Recently, writer and artist Sean Gordon Murphy concluded his Batman: White Knight limited series, which took place in an alternate reality where Batman was a much more brutal and reckless vigilante that in the regular DC Universe. In that universe, he only had two sidekicks: Dick Grayson's Nightwing and Barbara Gordon's Batgirl.

Both characters received a character re-design that saw the most recognizable traits kept intact, while being subject to a modern, more practical twist. In this universe, Batgirl's costume was closely inspired by a biker outfit. Her cape was quite short and more of a fashion statement than a tactical advantage, while the cowl only covered her face – not her head. This is one that could easily serve as inspiration for a film.

11 CASSANDRA CAIN

Cassandra Crain filled in for Batgirl after Barbara Gordon was shot and paralyzed by the Joker. While Barbara used her skills to become Oracle, a new Batgirl arrived on the scene, with a brand new costume. Cassandra was nothing like Barbara, and that was clearly reflected in the differences in costume.

Where Barbara used to be a bit more coloful, Cassandra's was all black – even her mask. There were no white eyes, no opening for her lower-face. Cassandra's Batgirl was covered in black, with only the golden outline of the Bat-symbol and her utility belt to show for color. Cassandra Cain is also set to appear in the DCEU movie Birds of Prey, and her costume will, hopefully, be just like in the comics.

10 ALL STAR BATGIRL

Frank Miller and Jim Lee's All Star Batman & Robin The Boy Wonder comic series took place outside of the main DC continuity. In it, we saw a modern iteration of the burgeoning partnership between Batman and Robin, and a teenage Batgirl would eventually come to debut on the series as well.

This Barbara Gordon had a costume that was different from the others seen in the character's history. Hers was dominated by black and yellow, just like Barbara's original comic book appearance, with the difference that she was wearing a domino mask. On top of that, her costume also set itself apart thanks to the appearance of seam lines, which gave a different kind of life to the costume.

9 YOUNG JUSTICE

Barbara Gordon's Batgirl made a few appearances in the popular animated series Young Justice, which focused on the sidekicks of the main superheroes of the DC Universe. While the series focused on Superboy, Robin, Aqualad, Kid Flash and Miss Martian, Batgirl did appear from time to time.

When she suited up as Batgirl, Barbara looked like she was truly the sidekick of Batman. Her costume was very muted compared to her more well-known fare. This version was meant to be stealthier, and there was barely any color to it outside of her belt and the interior portion of the cape. This is a costume made for crime-fighting in the dead of night.

8 DC REBIRTH

In the comic book world, Batgirl is currently about to change costumes once again. After rocking the same look for a couple of years, even through the DC Rebirth relaunch, Barbara is now set to change outfits. The new costume, designed by Batman: White Knight writer/artist Sean Gordon Murphy, is both classic and modern at the same time.

With a costume dominated by dark grey, with a yellow Bat-emblem and blue cape, this is a costume that calls back to one of the most beloved Batgirl costumes, as seen in Batman: The Animated Series. But Murphy's new design gives a modern update on the classic, which makes it one of the ideal inspirations for a live-action film.

7 FUTURE'S END

Future's End was a New 52 storyline that showcased the events of an alternate future. In it, Barbara Gordon, who would become a different kind of superhero, would launch the League of Batgirls, which contained three different characters fighting side-by-side in their own respective Batgirl uniform.

The three Batgirls were Cassandra Cain, Stephanie Brown and Tiffany Fox, and each had their respective colored symbol: yellow, purple and pink. Their suits were quite similar: they were tactical and armored. They had no capes whatsoever, and the length of the ears varied from long to short. We didn't see these costumes in action very long, but they still rank among the best. They were different, and they were still very much all Batgirl.

6 ARKHAM KNIGHT

In the Batman: Arkham Knight video game, users got to play as Batgirl for a few missions. In those levels, Barbara Gordon could be seen in an armored suit that closely resembled the high-tech suit that Bruce Wayne wore in the game as Batman. But, on top of that, it was also meant to be a modern take on her first comic book appearance.

Batgirl's costume had the appropriate modern armored aesthetic, but it also had the yellow symbol, utility belt and gauntlets that called back to her first costume. Realistically, Batgirl, like Batman, would need a heavily protected battle suit, which makes this one of the most accurate renditions of the Batgirl costume.

5 STEPHANIE BROWN

After Barbara Gordon and Cassandra Cain, Stephanie Brown was the next in line to become Batgirl, continuing the superhero's legacy. After Cassandra's all black take on the character, Stephanie became a very different sort of Batgirl, with a colorful costume that matched her brighter, much more hopeful attitude.

Stephanie Brown's costume as Batgirl brought back the purple and yellow of the Batman '66 colors to the forefront, and the leg strap would become a signature piece of the character. On top of that, this was the first version of the costume that would appear more tactical and practical – something that would become the norm in subsequent costume revamps.

4 ORIGINAL COMIC BOOK APPEARANCE

While Barbara Gordon debuted on television in a purple and yellow costume, her original comic book appearance in the same year saw her leap into action into a black suit that had a yellow symbol, gauntlet and belt buckle, and a bluish cape and cowl. This was the original Batgirl look, a classic that has stood the test of time.

In fact, this version of the costume is so iconic that it would be featured in The New Batman Adventures animated series, which was the revamp of the beloved Batman: The Animated Series. While it is the original costume, it is still viewed as one of the character's best.

3 THE NEW 52

After the events of Flashpoint, DC did a complete, line-wide relaunch that streamlined the universe's continuity and rebooted all of its major characters. In this relaunch, Barbara Gordon was the original Batgirl, and her costume was meant to offer a modern spin on all of the classics that came before.

Much like Batgirl's Arkham Knight costume, this was an armored take on the original comic book costume of the character. The armor was all black, with a golden Bat-emblem, utility belt, gloves and boots that called back to the character's first appearance. But instead of a blue cape, this one had a purple interior, as a nod to the original costume from Batman '66.

2 BATGIRL OF BURNSIDE

After the New 52 relaunch, DC updated its line of titles by introducing a new revamp that would become known as DC You. As part of this new direction, Barbara Gordon's Batgirl would ditch her more classic costume to don a new one that would become instantly beloved by fans and iconic in the character's history: the Batgirl of Burnside costume.

Designed by Cameron Stewart and Babs Tarr, this new costume looked like something that a teenage girl who lives alone and who doesn't have access to the massive wealth and technology at the disposal of Bruce Wayne would create. The cape snapped on, the costume was more of a jacket and the boots looked like they were bought at a store.

1 BATMAN: THE ANIMATED SERIES

Batman: The Animated Series features what is arguably the most iconic, classic version of the Batgirl costume, not only because it is one of the most recognizable, but also because it's one that stands apart from the rest. On the cartoon series, the character didn't wear a black or purple costume: it was one of the only instances where she wore grey.

This was most probably meant as a reflection of the Batman costume, which was also grey on the series. Still, the character's suit instantly came alive with a yellow emblem and utility belt. The rest was all grey, black and blue, and it is the version of Batgirl that you might be most familiar with – and with good reason.