Star Trek: Prodigy has always been a stealth sequel to Star Trek: Voyager, but the addition of 10 classic characters could make the continuation more explicit. Prodigy season 2 will continue the story of the young Starfleet hopefuls led by Admiral Janeway (Kate Mulgrew), as they work to rescue Captain Chakotay (Robert Beltran) and the missing crew of the USS Protostar. Now that Dal R'El (Brett Gray) and his young team are working directly with the real-life Janeway instead of a hologram, there's a possibility that they could interact with more characters from Voyager.
Actor Garrett Wang has recently stated that his Star Trek: Voyager character, Harry Kim belongs to Star Trek: Prodigy. This creates the possibility that more Voyager characters will appear in Prodigy as Janeway seeks help in locating Chakotay and his missing crew. Star Trek canon has established that, except for Seven of Nine (Jeri Ryan), many members of the crew of the USS Voyager are still serving Starfleet officers during the Prodigy timeline. This therefore allows many Voyager characters to appear in Prodigy season 2 and beyond.
10 Naomi Wildman
Naomi Wildman (Scarlett Pomers) was a child of the USS Voyager, being born aboard the stranded starship in the early days of its journey through the Delta Quadrant. As Star Trek: Prodigy is aimed primarily at a younger audience with a cast of young adults, it would make sense for Naomi Wildman to return. She formed strong relationships with Janeway, Seven, and Neelix (Ethan Phillips) during Star Trek: Voyager. An alternate future revealed that she got a field commission as a Starfleet Lieutenant, so Wildman could be in the early stages of her Starfleet career in Prodigy season 2. Her first assignment could be on Janeway's new ship, acting as a bridge between Dal's young crew and the Admiral.
9 Ambassador Neelix
When Neelix left the USS Voyager to live with a small group of Talaxians, Janeway offered him the role of Starfleet Ambassador to the Delta Quadrant. It was a role that Neelix gratefully accepted, suggesting that he could be of great help to Admiral Janeway in Star Trek: Prodigy season 2. The USS Protostar had originally been designed for a return mission to the Delta Quadrant, where it encountered a temporal anomaly. As Starfleet's Ambassador, Neelix could provide Janeway and the crew valuable information on the Vau N'Kat and the planet Solum, hopefully averting the catastrophic First Contact mission that created Star Trek's two 25th century timelines.
8 Lieutenant Icheb
Icheb (Manu Intiraymi) was one of the former Borg drones assigned to Seven during Star Trek: Voyager's later seasons. In an alternate future an adult Icheb (Mark Bennington) and Naomi Wildman (Vanessa Branch) were fully-fledged Starfleet officers. Star Trek: Picard established that Icheb continued to serve in Starfleet after the USS Voyager returned to the Alpha Quadrant, so he could easily be serving alongside Janeway in Star Trek: Prodigy season 2. However, the grisly fate that Icheb met with in Picard season 1 may bar him from appearing in a children's TV show, to avoid young viewers investigating what happened to him after Prodigy.
7 Lt. Tom Paris
As one of the main beneficiaries of Kathryn Janeway's willingness to give people a second chance, Tom Paris (Robert Duncan MacNeill) feels like a perfect fit for Star Trek: Voyager. It's easy to see Dal being impressed by a Top Gun Star Trek pilot like Tom Paris, who could be a mentor to the young man, keeping him away from the mistakes that Paris himself once made. As Janeway seeks to mold her young warrant officers into exceptional Starfleet officers, it would make sense for her to draw on the expertise of those who have previously benefited from her guidance.
6 Lt. B'Elanna Torres
Star Trek: Prodigy established that Lt. B'Elanna Torres (Roxann Dawson) oversaw construction of Janeway's ship the USS Dauntless, which was equipped with a Quantum Slipstream drive. Now that Janeway has seemingly left the Dauntless behind, she'll need a new starship with which to rescue Chakotay. It would make sense for B'Elanna to have also overseen the construction of this new starship, possibly even naming it the USS Voyager-A. Hopefully she'll be brought on as the new ship's Chief Engineer, clashing with the similarly hot-headed Tellarite engineer Jankom Pog (Jason Mantzoukas), and teaching him a thing or two about starship engineering in the process.
5 Q Junior
Star Trek: Voyager's Q appearances helped expand the story of the Q Continuum after his appearance in Star Trek: The Next Generation's finale. One of the new additions to Q lore was the creation of his son, Q Junior (Keegan de Lancie), who could easily slot into the story of Star Trek: Prodigy. His father Q (John de Lancie) now has his sights set on Ensign Jack Crusher (Ed Speleers) so it would make sense for Q Junior to instead put Dal R'El through his cosmic paces. As an Augment made up from aspects of multiple species, Dal could provide a fascinating source of study of for the Q Continuum. Janeway is also Q Junior's Godmother, setting up an interesting dynamic should he return for Prodigy.
4 Ensign Harry Kim
Ensign Harry Kim (Garrett Wang) could finally get his Starfleet promotion with an appearance in Star Trek: Prodigy. Harry's first assignment was as an Ensign aboard the USS Voyager, where he was taken under the wing of Captain Janeway. It would be fitting if Harry Kim was now in a more senior position, where he could help the young cast of Prodigy find their own place as junior warrant officers on a mission to the Delta Quadrant. It's known that, if showrunner Terry Matalas had his way, Star Trek: Picard season 3 would have introduced Captain Harry Kim, so Prodigy season 2 could reveal how Harry finally earned this 25th century promotion.
3 Seven Of Nine
Seven of Nine isn't in Starfleet during Star Trek: Prodigy, but she could be of great use to Janeway's mission as a freelancer. It's unclear if Seven "belongs" to Star Trek: Picard or if she can also appear in Prodigy. As It takes place prior to the events of Picard, it wouldn't compromise her promotion to Captain of the Enterprise. Instead, it could shed some light on her time in the Fenris Rangers, and Janeway's threat to resign in protest at Seven's rejection from Starfleet. Janeway is currently putting her neck on the line for Dal and his Protostar crew mates, so an appearance by Seven could reinforce how loyal Janeway is to those that are important to her.
2 The Doctor
Star Trek: Voyager's Doctor (Robert Picardo) had caused a stir in Federation society with a landmark case about his rights to be identified as author of his controversial holonovel. Sadly, the Doctor wasn't successful in winning the right to be seen as a sentient individual. However, Star Trek: Prodigy can revisit the storyline to finally give the Doctor the rights that he deserves. The rights of holograms to be recognized as individuals would have wide-reaching consequences for the Star Trek universe, providing some fascinating storytelling possibilities for future Prodigy episodes.
1 Captain Tuvok
The return of Tuvok (Tim Russ) in Star Trek: Picard season 3 suggests that there's no current plans for Janeway's Vulcan best friend to appear in Star Trek: Prodigy. This would be a missed opportunity, as the prospect of Tuvok putting the young warrant officers through their paces is an unmissable concept. Tuvok did something similar for the former Maquis terrorists that were integrated into the personnel structure of Voyager, causing tension between the two crews. Therefore, it would be hugely enjoyable to revisit the storyline for Star Trek: Prodigy season 2, with Tuvok leading Janeway's young charges, creating friction between the Vulcan and the wayward youngsters.