Mon Mothma

When Mon Mothma first appeared in 1983's Return of the Jedi, we knew nothing about her, but we could tell she was important. Her flowing white robes gave her a regal air in a sea of well-worn flight suits and combat fatigues (and Crix Madine's regrettable beard). In her few somber lines of dialogue, she clearly establishes the stakes of the upcoming battle over the forest moon of Endor. Her voice is almost haunting as she underscores the price of the information she and the Alliance's senior officers share with the assembled Rebels.

No one on-screen tells us she is the leader of the Rebel Alliance. They don't have to. 

Later on, in Canon, she leads the New Republic as its first Chancellor. She finally retires from public life sometime before the events of Bloodline, 24 years after the Battle of Endor.

She appears briefly in the background of a scene in 2005's Revenge of the Sith with other senators in the waning days of the Republic. A short speaking role, sadly, was deleted from the final theatrical cut. We see and hear more of her in The Clone Wars animated series, where she is a colleague and legislative ally of both Padmé Amidala and Bail Organa. Unsurprisingly, she and Bail work closely together in 2016's Rogue One: A Star Wars Story.

She also figures prominently in the Disney+ series Andor. Starting five years before Rogue One, the spy thriller tells how Cassian Andor becomes the intelligence agent we see in the film. But it also shows the early days of the Rebellion and how Mon Mothma, publicly a senator and secretly a key figure in the quietly growing movement.

Beyond the political intrigue and covert dealings, the series also shows us her home life. Her husband seems perfectly comfortable in the Emperor's New Order, and her teenage daughter is both rebellious and resentful. It's not immediately apparent that her double life is the source of tension in her home, but it certainly can't help. After all, building a rebellion under the Empire's watchful eye must be difficult.

As a pivotal figure in the Rebellion since the franchise's first trilogy, it's no surprise she also figures prominently in Legends. Building on Episode III's deleted scene, The Force Unleashed shows us her founding the Rebel Alliance with Bail Organa and Corellian Senator Garm Bel Ibis. In Heir to the Empire, she becomes the New Republic's Chief of State. In Dark Force Rising, we learn that over the years, her relationship with Bel Ibis had become strained to the point that he ultimately withdrew from the Alliance. In the Jedi Academy trilogy, she survives a nasty assassination attempt and prepares Leia to become her successor. 

Peer and friend to Padmé Amidala, confidant and mentor to Leia Organa, Mon Mothma is one of the few characters whose arc extends from before the Republic's fall through the Empire's defeat. Consequently, she appears often in both Canon and Legends books as leader of the Rebellion and, later, the New Republic. Some of those roles are bigger than others, and our list doesn't include some of the more minor appearances. But if watching Andor leaves you wanting to see more of Mon Mothma, any of these books would be a fine place to start.