Star Wars always finds a way to revisit beloved characters. The Disney era of the franchise has produced more Star Wars content than any other period, meaning it's very likely that the franchise will revisit some of its characters (it already is in the upcoming Andor series). However, some characters are more likely to return than others.
Either due to a lack of narrative possibility or a reluctance on the part of the actor or actress, some characters most likely will remain unique to the movies or series they appeared in. But for some fans, their most cherished characters are almost certain to return in some fashion. It's just a question of when and where.
Likely To Return: Qi'ra
Qi'ra from Solo: A Star Wars Story recently resurfaced in the War Of The Bounty Hunters storyline in Marvel Comics, lending a lot of weight to the idea this character will return at some point in live-action.
Now that fans know she survived well into the original trilogy and likely beyond, the sky is the limit for where this intriguing character could appear. Given her connections to the underworld, and specifically Boba Fett and Han Solo, it's very possible that Qi'ra is a character who could appear in The Book Of Boba Fett.
Unlikely To Return: Cara Dune
Given the controversy surrounding actress Gina Carano leaving The Mandalorian, it's very unlikely that Cara Dune returns to the franchise.
While Cara Dune could be recast, the character was inessential to the overall plot of the story. Cara Dune seems to have been more integral to the story of the potential Rangers Of The New Republic streaming series, which is no longer in active development. Though the character could return in some form in the future, the odds are mostly against it.
Likely To Return: Jyn Erso
With Cassian Andor getting the prequel series treatment, it's likely that the main character of Rogue One, Jyn Erso, could as well.
There are some things about Jyn Erso that don't make sense, so the franchise has another opportunity to explore her backstory and life before her sacrifice on Scarif. She could even appear in the Andor series, but not in a context where she and Cassian meet. Given the timeframe, she could also potentially be a character who appears in the upcoming Obi-Wan Kenobi series.
Unlikely To Return: Snoke
At one point, Supreme Leader Snoke seemed full of potential as a character. The revelation that he was some kind of clone or puppet of Emperor Palpatine, engineered on the planet Exegol in The Rise Of Skywalker, mostly settled questions fans had about him. It's unlikely he'll return in the future, at least in live-action.
With Snoke's origins explained, there wouldn't be much reason for Star Wars to revisit him, unless it would be in the context of exploring the fall of Kylo Ren. But Ben Solo is another character who fans may not see again, at least for a long time.
Likely To Return: Enfys Nest
Numerous characters populate the timeframe many upcoming Star Wars streaming series are exploring. Enfys Nest is one of the most intriguing ones.
The young freedom fighter and leader of the Cloud Riders has reasons to cross paths with numerous galactic heroes. Cassian Andor makes a lot of sense, but Obi-Wan Kenobi does as well. After Erin Kellyman's turn as The Flag-Smasher Karli Morgenthau in The Falcon And The Winter Soldier, fans know what a great actress she is. It's very likely Enfys Nest returns at some point.
Unlikely To Return: Captain Phasma
Though Captain Phasma is most likely dead after her fiery plunge in The Last Jedi, there was enough ambiguity around it that a return is plausible (Boba Fett survived the Sarlacc Pit, after all). But a return for the unique armored First Order warrior is unlikely.
The story potential for the character seems to have been spent in the sequels, and her interesting backstory has been explored in the comics and in a novel by author Deliah S. Dawson. Though it's possible, a return seems unlikely for the character.
Likely To Return: Ezra Bridger
It is very likely Ezra Bridger returns to the franchise. Given the fact that Ahsoka is hunting Grand Admiral Thrawn, the whereabouts of Ezra is one of the most burning questions the upcoming Ahsoka series can answer.
When fans last saw him, he disappeared into the Unknown Regions with Thrawn. His reappearance in live-action is all but assured unless his story is revealed to be tragic in the end. That's as unlikely as fans never seeing this Jedi on screen in the future once again.
Unlikely To Return: Kylo Ren
Though Kylo Ren is one of the most popular characters from the sequel trilogy, his death at the end of The Rise Of Skywalker closes the door on future appearances. He could return as a Force Ghost, but it's unlikely actor Adam Driver would come back just for a simple cameo or scene.
A series exploring a younger Ben Solo is certainly possible, perhaps with a different actor. For now, though, his story seems complete within the larger Star Wars narrative.
Likely To Return: Rey Skywalker
The hero of the sequel trilogy, Rey Skywalker is likely to return to the franchise at some point. Given her popularity and her place in the Skywalker lineage, any story that takes place after The Rise Of Skywalker is likely to feature her, depending on the timeframe.
Though The Skywalker Saga itself may be over, the future of the galaxy remains wide open and there's a lot of potential in seeing Rey and Grogu - who would still be a young child at that point - joining forces as Jedi to one day restore the order.
Unlikely To Return: Poe Dameron
Another major character from the Star Wars sequels, Poe Dameron is very unlikely to return. Actor Oscar Issac is on the record saying that he is not likely to come back to the franchise. The character could be recast, but without a compelling story, it's hard to imagine Disney going that route.
His story, for now, seems like it will be confined to comics and books unless Issac changes his mind in the future. Issac is currently set to play Marc Spector, the hero of the upcoming Moon Knight Marvel series.