Black holes are a pretty common feature in science fiction, whether for warping, power generation, etc. However, I can't recall any mention of them in Star Wars.
Are there any notable mentions of black holes in the Star Wars? Official Canon is preferred, but Legends and such are fine.
Legends Answer:
I only know of 2 books that mention them, Star Wars: Into the Void and Darth Bane: Rule of two.
In Star Wars: Into the Void the protagonists are trying to stop the antagonist from activating an ancient Gree device that would create a black hole,
It could destroy Tython," Dam-Powl said. "Exposing dark matter to normal matter would be cataclysmic. It would create a black hole, swallowing Tython in a heartbeat. The rest of the system, too."
Star Wars: Into the Void page 16, 25 793 BBY
and
"He's going to kill everyone, " seh said. "Once he initiates the device, the dark matter will form a black hole and everyone in the system-"
Star Wars: Into the Void page 185, 25 793 BBY
In the Darth Bane series they are searching for an ancient temple located on Tython (though 20 000+ years after Into the Void) which is near a black hole.
"Tython?" Zannah exclaimed, recognizing the name. "Isn't that one of the Deep Core worlds?"
The Deep Core was a small cluster of densely packed stars centered on a black hole in the very heart of the galaxy.
Darth Bane: Rule of two Page ???, ~1000 BBY
Everything within this core zone is a high security zone where travel is restricted due to the black hole and other shifting gravitational anomalies.
This black hole near Tython is the galactic core black hole mentioned in this answer.
In Canon, I can only think of 1 semi-example.
In the Star Wars Rebels episode Legends of the Lasat (Season 2, episode 14), the crew of the Ghost encounter an "imploded star cluster". I'm not sure what exactly an imploded star cluster is, but it sounds like a high-gravity area and the closest thing I know of to a black hole depicted in a Disney canon work.
In Legends, the answer is much more clear. There is the Maw which is a cluster of black holes. In and around the Maw resides various stations including the Maw Installation which was a secret weapons development station utilized by the Empire located inside of the black hole cluster.
This is a Legend answer.
The first thing that comes to my mind is the Maw. The Maw is a black hole cluster located in the Outer Rim near Kessel. This is where the Empire built partially the Death Star I and other weapons, like the Sun Crusher (from the Jedi Academy trilogy). The area is used in later novels, especially in Fate of the Jedi series where we learn that
the Maw was created to be a prison for the dark side entity Abeloth
Source: http://starwars.wikia.com/wiki/The_Maw
There is a great retcon with the movies and the Maw black hole cluster: smugglers used to fly near the Maw to avoid Imperial patrols. That's how the Millenium Falcon did the Kessel Run in less than 12 parsecs - basically flying near the black holes reduces the distance. More details here: http://starwars.wikia.com/wiki/Kessel_Run/Legends
There are several other black holes in Legends, like the Galactic Center. You can find a list here: http://starwars.wikia.com/wiki/Black_hole
Disney Canon
Star Wars: Heir to the Jedi
The problem with conspiracy theories is that they have their own gravity: they are black holes from which one rarely escapes - Drusil (p. 176, digital)
Both statements are said in-universe by characters
Merely thinking that refilled the empty space in the Force with even more rage, and I saw what kind of space it was, a black hole that would always be hungry no matter how much I fed it. - Luke (p. 256, digital)
Aftermath
The last thing Wedge wants to do is pilot around the edge of a black hole or through the center of a star going supernova - strange narrator, digital edition
Battlefront: Twilight Company
He'd spoken of a singularity in the galactic Deep Core. In the middle of everything, Gadren said, there was a black hole that devoured all light and energy, exerting a gravitational pull more powerful than a thousand suns. p. 187 digital
No explicit references in Dark Disciple, A New Dawn, Lords of the Sith, or Tarkin
