I've compiled a list of Star Wars novels that explore the life of Darth Maul from his early apprenticeship with Sidious to his downfall on Naboo and eventually a short story during his crimelord era where he goes looking for weapons to use against the Empire but find a ghost from the past instead.
Star Wars: Myths & Fables: 'An Unwilling Apprentice' by George Mann [Galaxy Edge Edition]
Plot: This short story explores Maul's childhood on Dathomir and how he became the Apprentice of Darth Sidious.
Notes: I believe the book is no longer in publication, but PDF copies can be found online.
This story fits into Disney's narrative and has replaced Maul's original story of being taken in by Sidious as a baby that was first written in the novel Darth Plagueis.
Star Wars Episode 1: The Phantom Menace by Terry Brooks
Bonus feature: 'End Game' by James Luceno
Plot: The written adaption of the film Star Wars: Episode 1: The Phantom Menace. Including missing scenes from Mauls perspective of his first duel against Gui-Jon Jinn on tattoine and how he moves past his failure into the next step of Sidious's plan for the trade federations occupation of Naboo.
Star Wars: Darth Maul: Shadow Hunter by Michael Reaves
Bonus feature: 'Restraint' by James Luceno, 'Saboteur' by James Luceno
Plot: Darth Sidious begins the first step into his master plan when one of the most important pawns to his mission goes missing, forseeing betrayal he sends his assasin Darth Maul to hunt down the missing Neimoidian.
Leading to a cat and mouse chase through the city streets of Coruscant, where the secrets become even more difficult to contain once they pass into the hands of an information broker and a rookie Jedi Padawan.
Star wars: Maul: Lockdown by Joe Scheiber
Excerpt: Honor Among Thieves by James S. A. Corey
Plot: Darth Sidious sends his assasin into a covert mission on board a prison ship to find a way to access a powerful weapon to aid in his efforts against the republic. Darth Maul faces off in a gladiator touranment against the most violent and deadly criminals in the galaxy in order to complete his mission.
Notes: The excerpt is not relevant to the story but merely an introduction to another novel about a prison break organised by Luke, Han and Leia.
Star Wars: Darth Plagueis by James Luceno
Excerpt: Darth Bane Rule of Two by Drew Karpyshyn
Plot: This story explores the life and death of Darth Plagueis; previously known as Hego Damask II, how he rose from his apprenticeship, into being the feared sithlord and master to sheev Palpatine aka Darth Sidious.
This story includes how Darth Sidious first came to find Darth Maul on Dathomir and the early days of his training.
Star Wars: The Wrath of Darth Maul by Ryder Windham
Plot: This story explores the early training of Darth Maul from childhood to teenage years and how he was sent to a training school called Orsis Academy for assassins, trackers, spies, and soldiers.
It explores his first friendship, his first betrayals, and his earliest interactions with the Death watch Mandalorians.
Star Wars: Episode 1: Journal: Darth Maul by Jude Watson
Plot: This is a journal style retelling of the events during The Phantom Menace told from Darth Mauls perspective.
Star Wars episode 1: Adventures 3: The fury of Darth Maul by Ryder Windham
Plot: Sidious send Maul out to retrieve something that has been stolen from him.
_______________________________________
Star wars: Stories of Jedi & Sith: 'The Ghosts of Maul' by Michael Moreci
Plot: Desperate for answers Maul goes raiding through ancient sith tombs and artefacts for weapons to use in his fight against Sidious, only to stumble across ghosts from his past.
__________________________________
This is not an extensive list. Feel free to add or recommend any of your favourite short stories or novels with Maul.
I will write a comic book/ graphic novel edition later. 💕