Since the birth of the franchise, Star Wars has had a lengthy and extensive list of additional content which has added to its lore. If the films weren't enough, fans could easily scratch their itch by looking at the myriad of comic books, novels and video games. No question went unanswered and no Lightsaber went unturned.
By the release of Revenge of the Sith in 2005, the juggernaut of a series had one of the largest extended universes in pop culture history. Even when George Lucas said that the 2005 film would be the final cinematic entry for the franchise, the pace didn't slow down at all, with additional media being pumped out at a higher rate, if anything.
This unfortunately all changed when Lucas sold the franchise in 2012. As soon as Disney took control of Star Wars, everything, apart from the films and the 2008 Clone Wars TV show, were labelled as 'Legends', essentially being dismissed as non-canon. Still, as time has gone on, more and more bits of Star Wars Legends have found their way back into canon, with more seemingly on the way.
10. Dark Troopers
Dark Troopers were upgraded battle droids that made their first appearance in 1995 shooter, Star Wars: Dark Forces. In the game, rebellious scoundrel Kyle Katarn infiltrates Imperial bases in an attempt to stop Moff Rom Mohc's Dark Trooper programme, facing off against these dangerous droids along the way.
In Legends, there were three distinct phases of the Dark Trooper. The Phase I trooper was essentially just a Lightsaber-resistant suit, equipped with a blaster and a vibrosword. Things picked up with the next iterations, with the Phase II trooper also having a jetpack and heavy cannon, and the Phase III trooper was virtually indestructible, due to it being made out of the metal, phrick.
Since then, these troopers have reappeared in several pieces of canon. In Star Wars: Rebels, Imperial Sentry Droids go up against the Ghost crew, which are Dark Troopers in all but name. Their first true canon appearance came in the second season of The Mandalorian, where Phase III troopers are sent to capture Grogu on Tython, and nearly kill Din Djarin in his effort to take his son back. These troopers are purely droids, but the fourth (and possibly final) iteration of the Dark Trooper was similar to the Phase III's seen in Dark Forces, with it being a powerful armoured-suit for Moff Gideon in The Mandalorian Season 3.