Season 2 of Supergirl saw her dealing with a lot of things. We got more complications in her love life, her relationships with family and friends, the signature that Lena Luthor wants to leave on the world, and most of all, how she is looking to chart a course forward, not just with other superheroes, but also with her cousin, Superman. Apart from the drama and emotional rollercoasters, she showed growth and that she was indeed worthy of carrying the sigil of the Kryptonian House of El, inspiring hope and fighting for truth, justice and the American way.

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Things ended with a mysterious threat arriving and that got us thinking that we could be seeing a few more villains and superheroes coming on board next year. We're hoping to see DC offer more faces -- the same way they do with the CW shows -- which won't be easy given that the DCEU is entering full-swing in cinemas and also, in terms of future productions. This series, however, has proven that even though it is on CBS, it has the legs to really fly the DC flag high, so with that in mind, CBR dissects who we'd love to see popping up next season, and who shouldn't!

SPOILER WARNING: Potential spoilers ahead for both seasons of Supergirl

15 SHOW UP: BRAINIAC

If Supergirl is to be truly tested, it should be by the very best that Krypton has to offer. There are sinister pieces of her Kryptonian heritage we would love to see in the spotlight next season, and when it comes to big baddies, few can rival Brainiac. Thus far, she's faced off against threats based mostly on brawn, so it's about time to get something more steeped in brains.

Brainiac would pose this cerebral threat, not just to her, but also to Superman as well. Given his arc in the comics involving the bottling of Kandor and other cosmic cities, whilst also harboring a huge vendetta for the House of El, he would make a great villain for the series (especially in the digital media realm) and bring a lot of traction to it, similarly to how he did for Smallville.

14 DON'T SHOW UP: DOOMSDAY

Doomsday using his laser vision in Batman v. Superman: Dawn of Justice

Doomsday isn't the answer all the time whenever a major villain is needed for Kal-El. This is even more-so the case in Kara's case, so seeing as this is her show, we'd prefer to explore villains that impact a lot on her. However, Doomsday's more of a Superman villain, so it just wouldn't feel genuine chucking him in here. In fact, it would feel like a prop -- a monstrous one at that.

Doomsday also doesn't fit the puzzle right now because we just saw him in Batman vs. Superman: Dawn of Justice, so it's best to get a little breathing room from Zack Snyder's behemoth. Finally, if he's done on a television budget, he should be done right. Smallville didn't accomplish this, so we'd prefer Supergirl takes its time before entertaining such a high-scale and destructive villain.

13 SHOW UP: FAORA

DCEU's Superman Faora Krypton Man of Steel

Faora wouldn't be an average villain for Supergirl to square off against. Instead, she'd be a major female powerhouse and one to test her boundaries. We saw Faora push Superman to the limit in 2013's Man of Steel, but fans should also remember she appeared in Smallville. After Superman hallucinated Supergirl as Zod at the end of last season, we'd love to see more Kryptonian criminals brought in.

Imagine seeing Faora and a couple thugs escape from the Phantom Zone and come gunning for the survivors of their race. Zod played a big part in BvS but Faora could have been given a bigger spotlight as she really kicked a lot of ass. That said, if Faora comes to town, she could disguise herself to torment Kara even more, as no one would be able to recognize the villain.

12 DON'T SHOW UP: SATURN GIRL

Saturn Girl showed up in Smallville along with Lightning Lad and Cosmic Boy, so to see her popping up as part of the Legion of Superheroes to perhaps hint to Kara of her future induction would be enticing, but sadly, overkill. Let's not convolute Supergirl's future here and make the show too complicated a la The Flash in terms of time travel and gifts from the future.

The LoS should be kept for Superman. There's a lot of girl power already on Supergirl, so we don't need to force-feed Saturn Girl to fans. Also, Kara seems to be maturing on her own, so any additional experience or sage advice could come from her cousin. Saturn Girl is being teased in the comics as a big part of DC's Rebirth at present, but when next she appears on television, it should feel organic and not gimmicky.

11 SHOW UP: MARTHA KENT

Martha Kent

After such a very important role in Snyder's BvS, why not transfer some of that familial love over to this series? Having Kara meeting and learning from her cousin is great fan-service and very heartwarming indeed, but one step further would be to see her getting that farm love and motherly treatment from Martha Kent in Kansas.

Martha's always been that sweetheart mother, whether it be in live-action, animation or comics, and having her help build the emotional side of Kara, and more so, the human side, makes sense because anything making Kara more of a daughter is welcomed. The more humanity and family there for our hero, the better because it makes for a more virtuous and endearing character. Kara in Kansas would help her coming-of-age story.

10 DON'T SHOW UP: POWER GIRL

Power Girl hails from an alternate Earth and boasts the same refugee history as Kara. However, she's Kara Zor-L and is seen as a more aggressive superhero. Bringing her in wouldn't be wise as we already got a Supergirl-Bizarro angle to play with so we'd like to steer clear of another hero or villain that's so similar to Kara. If anything, Power Girl could be kept for the multiverse trips the CW shows usually take.

Having another Kara could detract from the main one's journey and we want to streamline things into her development. Power Girl would be a gratuitous and unnecessary move to appease fans, and hey, how could we do that "boob window" costume true justice on primetime television? There's a time and place for everything, but for Power Girl, it ain't on the CW.

9 SHOW UP: GLORIOUS GODFREY

glorious-godfrey-justice-league

Glorious Godfrey would be a great addition to the series because he could start setting the stage for a media propaganda slant against the Kryptonian heroes. This would play up his role as a disciple of Darkseid and sew seeds for future appearances from Apokolips' leader, which could take a while given that the Justice League movie is laying building blocks for him in the DCEU.

Godfrey's media manipulation would fit the show, especially if he's given that twist of being an online blogger or a viral sensation that perpetuates witch-hunt campaigns against superheroes and altruistic meta-humans. He's been big in Justice League Unlimited, Smallville and Young Justice so he fits as a non-violent villain against Supergirl. Even if the show isn't allowed to tackle Darkseid, he'd still come off as a key antagonist.

8 DON'T SHOW UP: LOBO

Lobo Red Lantern

Remember when DC gave Lobo that controversial hipster makeover? Well, not even that iteration of Lobo would make sense over here in Supergirl. He just doesn't fit network television like he does all those cartoons. Unless we get Lobo cutting loose with no restrictions and going up against Superman or Supergirl as part of a bounty hunt, there's no true platform for him in terms of live-action. It's as simple as that.

This series just wouldn't be able to do the character justice. His foul-mouthed, cigar-smoking and bike-riding badassery wouldn't fit the teeny-bopping drama essence of this series. Lobo would be way too crude and overly abrasive, so let's honor him by not watering him down and forcing him in here. A diluted Lobo is a boring Lobo after all.

7 SHOW UP: DR. SIVANA

Thaddeus Sivana is an underrated villain in DC Comics and oddly enough, he hasn't been given much air-time in the live-action realm. He could hint at the Secret Society of Super Villains as per the comics, or even link to the Luthors in this series, but what makes him a major threat is that he's just as much an explorer of science as he is magic.

The latter often finds him roaming as a treasure hunter, tied to the lives of Black Adam and Billy Batson, so Sivana could open up the mystical realm of Supergirl in ways we never imagined. If not, then the show could just plug him in as the genius scientist he is. Think of Emile Hamilton at STAR Labs, and then picture Sivana as his polar opposite, wreaking havoc.

6 DONT SHOW UP: KRYPTO

krypto superman

We live in an age where we love seeing animals on the Internet and television. However, let's not jump the shark and ask for a super-powered dog here. Smallville actually featured the character, developed as a product of experiments with Kryptonite. Lois and Clark then tended to it, with Lois draping a red towel around the dog after giving it a bath, mimicking a cape. Instead of Krypto, they named it Shelby though.

That's about the only sensible origin story we can see for the pooch and it would not be cool if this was repeated for Supergirl. This series doesn't need unoriginality in its fabric, so no need to head down this road. Krypto would be a cute addition but it would feel like one that comes off as a prop. Plus, the city's no place for Krypto!

5 SHOW UP: MADAME XANADU

Magic Quiz Madame Xanadu

Madame Xanadu would be a huge left-field appearance but one that could expand on what the overall mystical world has to offer in Supergirl. She's been a supernatural figure that's factored into the lives of Constantine, Jason Blood and so many of the magical heroes and villains over at DC and Vertigo, but is yet to really get exposure on television.

She would be perfect for a one-off dive into the magical realm, even hinting at things like the Spectre and so on. She may not be able to fully reveal what the occult world has to offer, as DC may prefer that be kept for cinema or the CW, but this could add a nice expansive flavor to Kara's journey, further opening up her borders on the world as she knows it.

4 DON'T SHOW UP: MONGUL

Mongul holding Batman over his head

Mongul is a DC villain that's endured a lot. He's seen as a powerhouse and a gladiator as well, bent on conquering the galaxy. He may be too grand of a villain for this show though, even though he can be seen as a more intelligent, scaled-down Doomsday. Just shaping him properly with C.G.I. could eat a lot of the budget. We don't want a repeat of when Smallville botched Doomsday's appearance, do we?

The thing with Mongul though is that his best stories come with the planet destroyer, Warworld (a weapon similar to the Death Star), which again seems too big in scope for this show. This duo should be kept for cinema or at least expanded on in Young Justice. You don't want to sell your finest villains short on television at the end of the day.

3 SHOW UP: LEX LUTHOR

Lex Luthor and Lena

Lex Luthor has been mentioned in the show, but he's yet to be seen, as expected given his role in the DCEU. With his half-sister, Lena, trying to repair the damage his criminal career left, having Lex exonerated could see the return of Luthor Corp, him reviving a relationship with Clark (as Jimmy revealed they were best friends prior to incarceration) and once more, Lex trying to stir the pot of global rule.

Having both Supergirl and Superman to play with would make for amazing television, but it also offers Lex the chance to dig into CADMUS and look into cloning once more. He's already sent John Corben (a.k.a. Metallo in the comics) to torment Kara's life, so it makes sense for him to finally make his presence felt in person, especially against Lena.

2 DON'T SHOW UP: LOIS LANE

We've had some amazing Lois Lanes on television -- Teri Hatcher and Erica Durance were both brilliant. In the movies, Margot Kidder, Kate Bosworth and Amy Adams also did great jobs. However, Lois isn't a solution to be sprinkled on the franchise whenever and wherever. With journalism a big thing on the show, and now Clark appearing, many would be eager to see Kara and her friends run into the Pulitzer-winner, but let's not get ahead of ourselves.

Lois is anything but a supporting character or cameo. She's one of DC's queens and deserves a lot of the spotlight. If anything, adding her could already take away from the roles that so many women already play in Kara's life. If Lois is to appear, it should be in a season or two from now, not next year.

1 SHOW UP: SUPERBOY

Superboy was created by Lex Luthor using cloning -- incorporating his DNA and that of Superman's. This would be an amazing twist to the show, throwing in yet another family member for Kara and Kal to deal with. CADMUS could factor in here as it did in the comics, and it would not only provide a big enemy, but also (once they turn him good) a little brother for Kara to train.

Kon-El has been a big hit on Young Justice (which could even tie in later on to the Titans series in the works), and fans should also remember we got Conner Kent on Smallville. This means that the clone angle is there to be explored again. Lex could be an epic gateway to this, bringing them all together full-circle once more.

Let us know in the comments who you'd love to see... or not see... next year on Supergirl!