The Star Wars universe divided forever in 2012 into canon and Legends, collectively the books, comics, and animated fare (and the infamous Star Wars Holiday Special) that Lucasfilm now considered apocryphal. Some characters have found their way back into canon, like Grand Admiral Thrawn in Star Wars Rebels, and some major events could still be reincorporated as well.
Since Disney acquired the franchise, creators have been cherry-picking characters and moments from Legends for new movies and series, and that trend is likely to continue as the Star Wars universe expands in the era of streaming. As it does, some major Legends storylines could come into play.
Jodo Kast Impersonating Boba Fett
One classic moment from Legends that could easily happen in the near future is the appearance of Jodo Kast in The Book Of Boba Fett. Jodo Kast first appeared in the Dark Horse Comics in the 1990s, before the prequel era properly began.
He impersonated Boba Fett after the apparent death of the bounty hunter and when Boba Fett turned up very much alive, he didn't appreciate it. An imposter Fett could work easily into the upcoming Boba Fett series, especially with Cobb Vanth already being established as something of a 'double' for Fett.
Anakin Skywalker Vs. Asajj Ventress
Anakin Skywalker and Asajj Ventress fought in some of the best episodes of the Clone Wars 3D animated series. But it's their duel on Yavin 4 in the initial 2D Clone Wars micro-series from Genndy Tartakovsky that should be canon as well.
This iconic battle is notable not only for its great action and choreography but for the way it gradually eases Anakin closer to the dark side. He eventually claims Ventress's own red saber from her, and his angry cry at the end of the battle is a great example of his inner torment.
The Rule Of Two
Darth Bane is a major figure in Sith lore, but his most critical contribution, the Rule Of Two, remains in the nebulous area of Legends. The concept was first mentioned in the adaptation for Star Wars: Episode I - The Phantom Menace in 1999, and then explored in the now Legends trilogy of books Path Of Destruction, Rule Of Two, and Dynasty Of Evil.
The books, written by Drew Karpyshyn, explore the origins of Bane, his apprentice Darth Zannah, and the beginnings of the Sith edict that would last into the Empire.
The Formation Of Wraith Squadron
Wedge Antilles returned to Star Wars in The Rise Of Skywalker in a brief cameo, but his story could continue in canon if Lucasfilm were to canonize the Wraith Squadron. Wedge is famous as the leader of Rogue Squadron, and could conceivably appear in the upcoming Patty Jenkins movie, but he formed a new squad in Legends.
The Wraith Squadron books by Aaron Allston showcased Wedge putting together a new squadron of pilots with a variety of talents in the New Republic era of the galaxy, all capable of carrying out different missions.
Luke Meets The Nightsisters
Luke Skywalker has returned to live-action in The Mandalorian, and that means he could possibly star in further adventures in the timeline of the show. If he does, that would open the door to one of his most interesting Legends encounters.
Luke travels to Dathomir and encounters the Nightsisters in the 1994 novel The Courtship Of Princess Leia, written by Dave Wolverton. The book takes place about eight years after the Battle of Yavin and featured Luke's unlikely alliance with a Nightsister named Barukka.
The Rise of Lumiya
Luke had another encounter with a female dark side user in the original Marvel Comics. Lumiya had once been Shira Brie, an X-Wing pilot revealed to be a Rebel spy.
After she betrayed Luke, she was injured and became the cybernetic Sith Lord Lumiya. Her story would be a fascinating one to explore in canon, as she remains one of the best original villains from the '80s comics. Given the appearance of Legends characters like Thrawn in canon, it's easy to picture key Legends characters luke Lumiya appearing in live-action.
The Apprenticeship Of Darth Sidious
Another major Legends event that could be brought into the canon is the apprenticeship of Darth Sidious. His tutelage under Darth Plagueis, a Sith Lord who could appear in a Disney+ project, was detailed in a novel by James Luceno, Darth Plagueis.
Though Plagueis himself is canon through Palpatine's dialogue in Revenge Of The Sith, his exact nature as described in the book is not. The book remains popular, and the secret history of the greatest villain in Star Wars history remains fertile ground for future content.
The Great Hyperspace War
Knights Of The Old Republic remains one of the most popular eras of Star Wars lore in Legends, to the point some consider it better than the original trilogy. Fans continue to clamor for KOTOR to be brought into canon, and there are major events from the era that could be, including the Great Hyperspace War.
This huge story, told over the comic book volumes Tales Of The Jedi: The Golden Age Of The Sith and Tales Of The Jedi: The Fall Of Sith Empire, The Great Hyperspace War is the result of early galactic hyperspace mappers discovering the ancient Sith Empire. The end result is a brutal intergalactic war for the ages.
The Great Sith War
The Great Sith War takes place almost 4000 years before the Battle Of Yavin and involves some of the most compelling characters from the KOTOR era, including Exar Kun and Nomi Sunrider.
The massive war spun out of the Jedi Freedon Nadd becoming a Sith, and the descent of Jedi Knight Ulic Qel-Droma into darkness. He eventually joins forces with Exar Kun, betraying the Jedi and a cataclysmic battle on Coruscant between the Sith and Jedi for the fate of the galaxy.
The Emperor's Hand
Mara Jade is perhaps the most significant Legends character who hasn't been canonized so far. She debuted in the classic novel by Timothy Zhan Heir To The Empire, alongside Grand Admiral Thrawn. Mara Jade was secretly the Emperor's Hand, an assassin who carried out his dark orders.
Her last mission to kill Luke Skywalker in revenge for the death of her master. Things turned out unexpectedly for her. She and Luke eventually married in Legends continuity and had a child. Though she's yet to appear in canon, there has been some set-up for the character.