Warning: This list contains spoilers for the Dexter New Blood finale.
Showtime's Dexter: New Blood finally got the ending that so many fans call "worthy." After fans named the ending of Dexter one of the worst TV series conclusions of all time, the original showrunner returned a decade later to right those wrongs.
With that said, while there's some finality for the character of Dexter, fans did enjoy the sequel series. And even though it was dubbed a limited series, fans have expressed interest in seeing more. There hasn't been an official announcement about a season 2, but if one was to come to fruition, potentially even a spin-off, there are some interesting angles that could be explored.
Harrison Becomes The New Lead
The most obvious spin-off series would be one with Harrison as the lead character, given that he was one of the most likable characters on Dexter: New Blood. The show could explore life in a new town on his own as he tries to reconcile what happened. He killed his father when he realized the Dark Passenger might be "in the driver's seat," as he noted, and not along for the ride as Dexter wanted him to believe.
Harrison seemed to genuinely want to shed his Dark Passenger and be "normal" versus Dexter, who simply wanted to appear "normal" so he could blend in. So, it could be an entirely unique story as Harrison fights his demons instead of embracing them.
Dexter Is The New Dark Passenger
Further to the above theory, if Harrison were to be battling his internal Dark Passenger demons, there would have to be a character to represent that demon, and/or a conscience. In Dexter, it was Harry Morgan and in Dexter: New Blood, it was Debra. For a potential spin-off, it could be Dexter who returns as Harrison's Dark Passenger or conscience.
It would allow for a brand-new story while also keeping Michael C. Hall, who made the character of Dexter famous, within the cast.
Angel Batista Tries To Clear Doakes' Name
The last fans saw of Angel, he was en route to Iron Lake to bring Angela all the information he had on Maria LaGuerta's death. He had also just learned that Dexter had been alive the whole time and was very likely the Bay Harbor Butcher.
But the story ended before Angel arrived. Fans would love to see a continuation story as Angel then tries to posthumously exonerate his former friend Sergeant James Doakes and break the news to others that Dexter was the killer all along.
Angela Realizes Harrison Might Be Like His Dad
Angela, one of the best new characters on Dexter: New Blood, seemed convinced that Harrison didn't know anything about what or who his father really was and was just a normal teenager who was dealt a bad hand. She had no idea that Harrison had inherited his father's Dark Passenger as well, likely due, at least in part, to the trauma he encountered as a child with the death of his mother.
Would Angela eventually put two-and-two together? She might realize Harrison was responsible for the stabbing incident at the school, then hear about the wrestling incident. She could then be desperate to find him guilty and he might kill, believing it would be her fault for letting him go.
Dexter Somehow Faked His Death...Again
It is a longshot, but while fans felt that Dexter's death allowed for satisfying closure, even predicting his guilt in theories on Reddit about how Dexter: New Blood would end, some don't want to believe it's true. Stranger things have happened, but given that Dexter is a blood-spatter analyst, he could have figured out a way to wear a bulletproof vest rigged for fake blood to seep out of his back. He would know how to make it look convincing.
It's possible Dexter ran off at some point while Angela was calling for back up and got away to start a new life somewhere else. But this time, he would also need to hide from his son, knowing Harrison would expose and/or kill him if he ever discovered that Dexter was still alive. It sounds completely implausible, but Dexter did already fake his death once before.
A Prequel Series About The Code
A popular method for extending popular TV shows and characters is the prequel series, as has been done with shows like Better Call Saul, a prequel to Breaking Bad, and Young Sheldon, a prequel to The Big Bang Theory.
A prequel series could explore Dexter's life after having lost his mother and leading up to the time when Harry recognized his Dark Passenger. While it might be difficult for Hall and Jennifer Carpenter, who played his half-sister Debra, to play themselves as teenagers, using different actors could make for an interesting story. The focus could be on Harry and the inner turmoil he experienced after first realizing who Dexter was, then trying to deal with it, only to eventually come up with his plan for The Code.
Hannah Isn't Really Dead
Harrison revealed that Hannah died from cancer several years prior, but there was never any proof that this was true. It is possible Harrison decided to run away and find his father once he happened upon the letter Dexter wrote to Hannah all those years ago.
A storyline could show that Hannah was not only still alive but had recognized Harrison's Dark Passenger and decided not to contact Dexter to tell him. Hannah might have been trying to track Harrison and Dexter down the whole time only to end up in Iron Lake and crossing paths with Angela and the others.
Kurt Caldwell Copycat Killer
Kurt Caldwell was one of the most sinister serial killers within the Dexter universe, arguably second only to the best serial killer on Dexter, Trinity. The discovery of the women he cleaned up, dressed in white, and kept embalmed in pristine condition in individual boxes over the years was very disturbing. But it never really got a proper finish except for Angela calling it in to the police.
While Kurt Caldwell is dead, chopped to bits by Dexter, that doesn't rule out the possibility of a copycat killer. Introducing someone who tries to replicate Kurt's methods and re-start his underground burial ground would make for a compelling story. It might not include Dexter, but the killer could look to old stories about Dexter for inspiration.