When it comes to animated television shows in the Star Wars franchise, The Clone Wars has, does, and will continue to get most of the love from fans, and it deserves every bit of it; it is one of the most incredible things ever created in the franchise. However, due to this, Rebels often gets underappreciated and deserves more recognition for its brilliance.
The show introduced so many fantastic characters in the franchise. As is always the case with Star Wars, there is a broad spectrum of morality, with some being evil and/or hatable, and others being heroes whom fans adore, with some falling in the middle.
The Inquisitors
The various Inquisitors in Rebels are fantastic villains for the show and help massively as foils for the characters, especially the Grand Inquisitor, pertaining to Kanan and his journey.
After the Grand Inquisitors spectacular death in season one, the Seventh Sister and Fifth Brother came into the fold, with the Eighth Brother also briefly appearing. None were in the show too long, but they left an impact and were the dogs of Vader, sent to hunt Jedi; with that being their only true purpose, they have no real redeeming qualities.
Grand Admiral Thrawn
This entry for Thrawn can pretty much act as an umbrella for the Imperials/other villains audiences get to know from this show, such as Pryce and Rukh, with Thrawn being the central antagonist of it all.
He is a fantastic character and a genius in a wide variety of topics, but that does not take away his status as a Grand Admiral in the Empire who seeks to oppress and to destroy the heroes of the story.
Maul
Maul is a fascinating villain, and if you told someone in 1999 who just saw The Phantom Menace that Maul not only survived but created a criminal empire and lived long into the days past the prequels, they would have called you crazy.
In Rebels, he has lost everything and has only revenge on his mind as he seeks out Obi-Wan. He is, as always, incredible, and his blind hatred and anger finally result in a swift death at the hands of Obi-Wan, and a moment of humanity from the iconic villain.
Chopper
Chopper is a droid with a lot of attitude, and who provides a lot of laughs throughout Rebels. He also cares deeply about Hera and is loyal to the Ghost Crew, but he is the least likable of the crew from an in-universe standpoint, even if so many fans love him.
Not only is he extremely lazy, attitudinal, and stirring up trouble regularly, but he has a violent, murderous streak to him. He may well be the best droid in the Star Wars franchise, definitely the best TV original one and the funniest, but unless you are Hera, it would be hard to get on with the little guy.
Alexsandr Kallus
There is a case to be made that Alexsandr Kallus deserves a place higher or lower on this when you take into consideration both his time as a member of the Empire, but also his defection from it.
It is his relationship with Zeb and the apparent guilt he feels for the things he has done that put him here. When he defects, he truly is a rebel, putting his life in all sorts of danger to aid the alliance as Fulcrum, and does so much to make up for his mistakes.
Ezra Bridger
Many people were not on board with Ezra Bridger as a central protagonist in the first season or two of the show. He was immature, a bit whiny and annoying, and some fans wrote him off.
However, his arc across the four seasons is fantastic, and he truly grows and matures into a great character. Nevertheless, there are some valid criticisms of Ezra, and he did go through a whole arrogance phase, so it does make him the least likable of the non-droid Ghost crew.
Sabine Wren
The same things that got said about Ezra also got told about Sabine Wren, another young gun in the crew of the Ghost, and a character who took a good while to blossom into her own.
When she did, though, she was great, as a cast out Mandalorian, there was always going to be good stuff with her, and it delivered. She made up for all her past mistakes, and even if she was less fleshed out than other characters for a long while, she was still an enjoyable, likable member of the show.
Garazeb Orrelios
Garazeb Orrelios, better known as Zeb, is a more challenging character to rank in terms of likability. He is by far the least developed of the Ghost crew, excluding Chopper, only really growing in terms of his fantastic friendship with Ezra.
Nonetheless, Zeb is a consistently nice character with a definite angry side quickly brought out by other characters. He may not be the most deeply explored redeveloped character, but he is still a significant part of the show.
Rex (Wolffe, & Gregor)
When The Clone Wars got prematurely canceled, one of the biggest questions was the fate of Rex. Did he succumb to Order 66? Did he survive? All questions got answered in Rebels when he returned with Wolffe and Gregor, two other beloved clones.
Rex became a crucial part of not only the show but the rebellion, after finally getting convinced to come out of retirement and exile by Ezra and a bitter Kanan. Rex, Wolffe, and Gregor had gotten their chips removed and were just as good in this show as they had been previously.
Ahsoka Tano
When Ahsoka Tano was first introduced to the Star Wars fandom, she got met with a universal meh, with fans annoyed by her instantly. However, when the series started going, she became a phenomenon.
Like Rex, many fans speculated her fate after the cancellation of The Clone Wars, and, thankfully, her story continued in Rebels, where fate led her to a face-off with Darth Vader. Ahsoka is pretty much the same as she was at the end of The Clone Wars, except she is far more mature and confident in her status as not a Jedi, but just a force for good.
Hera Syndulla
Hera Syndulla is the leader and mother figure of the Spectres; she brought everybody together and created a family that would help massively in the fight against the Empire.
Hera is an incredible pilot, a passionate fighter, and someone willing to do anything to protect the ones she loves and fight for the rebellion to help innocent people. Her selflessness, passion, leadership, and various other attributes shine through across all four seasons of the show.
Kanan Jarrus
Ezra Bridger got positioned as the main protagonist of Rebels, but most people agree that the character with the best journey throughout the show is his master, Kanan Jarrus, formerly Caleb Dume.
Justa bout every character in the show has a relatability factor for fans, and Kanan is no different as he struggles with his self-worth, believing himself not to be good enough to train Ezra or be a Jedi. He is one of the best characters of this new era, and the standout from this show, although there are definite arguments for other characters being more likable.