The Suicide Squad movies excel at introducing characters that aren't as well-known to a wider audience. Other than comic book readers, many people haven't been familiar with the likes of Weasel or Ratcatcher before Suicide Squad recently premiered.
The third film focused on Task Force X could very well continue in this trend, and bring even more comic book characters into the spotlight. Most of the following characters haven't had their chance to shine in films or TV shows just yet. Their presence would bring a lot to the new Suicide Squad, though, either thanks to their powers or because of their absurd designs and personalities.
10 Mindboggler
Unlike other characters, Mindboggler joined the Suicide Squad willingly. As her nickname suggests, she can manipulate the minds of other people and cause hallucinations. Seeing her in the next film would be a lot of fun, since it would allow the audience to learn more about the characters.
In the comics, Captain Boomerang eventually lets Mindboggler die because she had previously embarrassed him. However, since he's gone, she could very well survive longer in the DCEU, letting audiences bond with her.
9 James Gordon Junior
Unlike his sister Batgirl, James Gordon Junior doesn't stand on the side of heroes. In fact, he couldn't be any more different from her — after all, he's a serial killer. He looks civil and polite at first, but he can be truly merciless.
James would stand out like a sore thumb among his more over-the-top team members, but could easily become the most frightening of them all. Plus, bringing him into the fold for the next film would create a stronger connection with the rest of the DCEU.
8 Black Spider
Black Spider isn't as interesting for what he can do, but rather because of how he behaves. Unlike most of the members of Task Force X, Black Spider actually had the chance to leave the team as Amanda Waller didn't kill him. She gave him the option to go where he wanted, but Black Spider refused.
This interaction would create an interesting dynamic between him and the other squad members, who want nothing more than to leave. Just like Peacemaker, Black Spider betrayed his team later on, and tried to murder Amanda Waller. Since the film has suggested others could take Waller's place, perhaps this could be the way it could come to pass.
7 Bronze Tiger
The team already has two animal-themed members, Ratcatcher 2 and King Shark. If it decided to include Bronze Tiger as well, it could create an interesting tension between him and King Shark. After all, sharks and tigers aren't usually friends.
Despite being a member of the Suicide Squad in the comics, Bronze Tiger is actually a somewhat decent, moral person. This would be a welcome change in comparison to more ruthless members of the team, and lead to some interesting team dynamics.
6 Parasite
Judging by his powers, Parasite isn't a C-List villain. He could, in fact, be one of the most powerful ones. However, he's not as widely known as many other DC characters.
Parasite's powers could wreak havoc among his fellow team members, as he can mimic the abilities of anybody he meets. He was even able to defeat Superman multiple times in the comics. If the team goes against an even bigger enemy in its next film, having Parasite's powers on their side would be a massive advantage.
5 Nemesis
Just like Mindboggler, Nemesis' powers could lead to some intriguing visual scenes and confusion among the team members. Nemesis is excellent at disguises, and can pretend to be virtually anyone. He even pretended to be Amanda Waller at one point in order to save her life.
Nemesis would be perfect for team missions that involved infiltrating various places. His presence could also lead to some fascinating scenes, such as two appearances of Harley Quinn at the same time.
4 Gentleman Ghost
The DCEU Suicide Squad already has a shark as its member, so who says it couldn't have a ghost as well? Gentleman Ghost has an added advantage in comparison to other team members: since he's a ghost, it's very difficult to hurt him.
Plus, his specific way of behavior would no doubt baffle the team. Considering the way he functions with his incorporeal form, this could lead to some pretty funny scenes.
3 Plastique
The Suicide Squad seems to excel at causing chaos. They're not above blowing things up, as they demonstrated in Jotunheim. With that in mind, Plastique's powers would fit their style. She can change anything into explosives just by touching it. That would mean the team would never run out of explosives, as long as Plastique stayed alive.
Plastique is also one of the characters who walk on the fine line between being a hero and being a villain. This would differentiate her from other Suicide Squad members, adding some interest to the character interactions.
2 Chemo
Appearance-wise, Chemo is one of the most unusual Suicide Squad members. His presence would fit in well with the films' over-the-top tone, though. Chemo is a walking jar full of deadly chemicals brought to life, which would make him stand out even in the company of someone like King Shark.
His presence could be hilarious, if the films got this unique character just right. Additionally, it would be a fantastic feat of visual effects onscreen.
1 The Writer
The Writer is by far one of the strangest Suicide Squad members of all time. He's an alter ego of Grant Morrison himself, who wrote his persona into the comics. He joined the team for just one mission, designed to defeat Circe.
Similar to Deadpool's style, the Writer realizes he's now a part of the story and somebody else, another writer, controls his fate. That could lead to some meta jokes, and also confuse the other team members who would have no idea what's going on. In the comics, he meets his untimely end soon enough...because he suffered from writer's block.