Throughout the films, it's clear that some Death Eaters are better than others, or rather, braver than others. Several Death Eaters were brave in Harry Potter, immorally courageous, but perhaps a few characters' courage against Voldemort caused their redemption.
A character's development plays a significant role in measuring bravery; it shows that a character isn't just brave but that they also can redeem themselves for their evil behavior. Death Eaters are undoubtedly the villains of Harry Potter. A few don't deserve any form of redemption arc because their "bravery" is rooted in their prejudice. But, a couple of characters show that character development means that they are learning from their past mistakes, growing, and hopefully becoming better people in the long run.
Peter "Wormtail" Pettigrew
Although Peter Pettigrew is undoubtedly one of the weakest characters in Harry Potter, it must be acknowledged that betraying Lily and James Potter and the rest of the Mauraders took courage. Although, it should be noted that Wormtail is one of the least brave Death Eaters, and his "bravery" in betraying the Mauraders stemmed from his fear of Voldemort.
Peter Pettigrew's fear, driving his acts, is the main reason he is a static character without character development. All of his behaviors are made to ensure his survival on the winning team, an attribute that is both unsavory and weak, making him nowhere near redeemable.
Lucius Malfoy
Lucius, an ever complex and interesting character, is still braver than Wormtail because of his ability to walk away in the battle at Hogwarts. He finally prioritizes his family (something he's never been able to do before). He chooses them over Voldemort in the end, making him slightly braver than Peter Pettigrew.
Lucius choosing his family over Voldemort shows character development for himself and that he's trying to become a better person by leaving Voldemort behind. This is something that Lucius was never able to do in the past, even if it meant for Draco losing his innocence and childhood by encouraging him to become a Death Eater.
Augustus Rookwood
Augustus Rookwood's efforts as a double agent were 'brave' in that it takes courage to be a double agent with Voldemort, but he also showed a form of bravery in the Battle of Hogwarts - rushing into the fight despite the risks.
Although Aberforth Dumbledore is the one who stuns him in the end, Augustus still had his own courage as a fighter for Voldemort, and for putting a target on his own back for being a double agent. Unlike others, too, his loyalty to Voldemort never falters, and he is with him to the end.
Narcissa Malfoy
Narcissa is not technically a Death Eater; but she supported Voldemort until she lied to him about Harry being dead, despite him being alive. Even though she only did this to ensure the survival of Draco, she could have easily turned Harry into Voldemort.
This act of kindness took extreme bravery and courage, making Narcissa a redeemable character who proved her ability to become a better person. Once Harry confirmed that Draco was alive, Narcissa could turn him in. Still, she instead chose to go against Voldemort and rise to the occasion of becoming a better person.
Igor Karkaroff
Igor Karkaroff's bravery comes from his turning in Barty Crouch, Jr., to save himself from Azkaban. Even though his disloyalty could be considered cowardly and self-serving, it takes bravery to go against the Dark Lord and turn in one of his most loyal servants.
Igor's character development comes from his ability to turn over a new leaf as the Headmaster for Durmstrang, even though he went into hiding at the rebirth of Voldemort and was eventually found dead. Clearly, like Pettigrew, his bravery was always self-serving.
Barty Crouch, Jr.
Barty Crouch, Jr. is one of the braver Death Eaters, having taken polyjuice potion for an entire school year, fooling everyone, including the chosen one, into believing that he was, in fact, Mad-Eye Moody. This took a lot of bravery to infiltrate Hogwarts and convince everyone of his false identity - especially as this meant working for Voldemort right under Dumbledore's eyes.
So, ultimately, Crouch Jr. is a courageous Death Eater that stays loyal to Voldemort until the end when a dementor sucks out his soul. Even though Crouch Jr. is an incredibly immoral character with terrible judgment and prejudice, he is still a reasonably brave Death Eater.
Bellatrix Lestrange
The bravest Death Eaters are kicked off with Bellatrix Lestrange. Bellatrix isn't 'the' bravest because she runs at the end of Order of Pheonix when Voldemort and Dumbledore reveal themselves at the Ministry of Magic. Unlike Wormtail, her cowardice balances out her usual bravery and desire to kill anyone and everyone that gets in the way - and this is one of the few times she appears cowardly.
In the end, Lestrange died fervently for her cause, and was one of the few brave enough to continue to stand by Voldemort, even through years in Azkaban, when most others were claiming to have been cursed and forced to follow him. Even though Bellatrix is extraordinarily prejudiced and evil, she is still an objectively brave person.
Regulus Black
Regulus, Sirius Black's younger brother, was a fearless supporter of Voldemort at the beginning of his reign. However, once he learned that Voldemort was making Horcruxes, he stole a Horcrux and was eventually killed by an Inferi.
Because Regulus stole a Horcrux and successfully hid it from Voldemort, and because he not only turned against him, but turned against him to actually fight him, Regulus is braver than he gets credit for. Even though he couldn't destroy it, it makes him one of the bravest Death Eaters in Harry Potter because he was one of the only Death Eaters to really fight someone so powerful.
Draco Malfoy
Not only does Draco have some of the most exciting character development throughout the series, but he also chooses to change sides at the Battle of Hogwarts after Harry saves him from a fiery death in the Room of Requirement. Even though he decides to walk back to Voldemort after the fact, he is reluctant and only does so because he thinks Harry is dead. Once it's revealed that Harry is, in fact, not dead, he leaves with his parents, leaving Voldemort for good. Earlier in Deathly Hallows Part 1, Draco refuses to confirm with Bellatrix that Harry is at the Manor after Hermoine used the stinging spell on his face. This is another scenario when a Malfoy chooses to support Harry instead of giving him up to Voldemort.
Additionally, there's evidence throughout the films showing Draco regrets becoming a Death Eater and even did so that he could finally gain approval from his father. Although Draco does support the Pure Blood ideology of the Death Eaters, he doesn't share their same philosophy for murdering innocent lives. Furthermore, his bravery in renouncing Voldemort not once but twice is what brings him up to one of the bravest Death Eaters.
Severus Snape
Many would argue that Snape isn't courageous at all, that he's a coward who killed Albus Dumbledore, but Dumbledore knew it was coming. When Snape gave Harry one of his tears at the end of Deathly Hallows Part Two, the audience could see what happened; Dumbledore knew of Snape's involvement all along, and even told Snape to kill him.
Over the years, Snape proved himself as the bravest Death Eater because he was with the Order and was a double agent for Dumbledore all along. So, despite his disloyalty, in the end, Snape is the most redeemable Death Eater and, in turn, the bravest Death Eater. In the end, Snape did everything he could to protect those he loved, including Harry Potter, which is undoubtedly brave.