Yes, there are some great Anakin kills Palpatine fanfics. You can try searching on fanfic platforms like Archive of Our Own. Some fanfics might explore different motives for Anakin to kill Palpatine, like a sudden realization of Palpatine's true evil nature before it's too late in the timeline. Others could be set in alternate universes where Anakin has a different backstory or set of circumstances that lead him to take this action.
One possible plot could be that Anakin discovers Palpatine's plan to destroy the remaining Jedi earlier than in the original story. This early discovery gives him the chance to turn against Palpatine and kill him to save the Jedi order. Maybe he finds some hidden evidence that convinces him once and for all of Palpatine's true intentions.
It could be that a powerful wizard in the Harry Potter universe sends Harry to defeat Palpatine for some greater good. Harry's quick thinking and his array of spells like Expelliarmus or the Killing Curse (although he hates to use it) could potentially be used against Palpatine. Since Palpatine is used to dealing with lightsabers and the Force, Harry's magic could catch him off - guard.
There could be. Fanfic writers often like to take the established 'Star Wars' lore and turn it on its head. Darth Plagueis was Palpatine's master, and the idea of him killing Palpatine goes against the canonical story, but that's the beauty of fanfic. It allows for creative and unexpected twists. You could try searching on platforms like Archive of Our Own or FanFiction.net with relevant keywords.
The Harry Potter universe might see an influx of new magical knowledge from the Star Wars galaxy. Since Harry has interacted with it, there could be new spells or magical concepts brought back. In the Star Wars universe, without Palpatine, Luke Skywalker and the other Jedi might not have to face as many challenges. However, the dark side would still be present, and new threats could emerge. And the relationship between the two universes could become a major point of study and diplomacy for both sides.
The plot might involve Anakin being influenced by the good side of the Force more strongly. He starts having visions of a dark future if Palpatine continues to rule. Anakin then starts to secretly gather allies, including some Jedi who have survived Order 66. Together, they plan an attack on Palpatine. Anakin, with his enhanced power, confronts Palpatine directly. Their battle could be not just physical but also a battle of wills, with Anakin finally emerging victorious as he overcomes the dark side's allure within himself.
It would have a huge impact on the characters. For example, Luke and Leia would grow up in a very different environment. Without Palpatine's influence, the Rebel Alliance might not have had as strong a cause, but there would still be a need to restructure the galaxy. Anakin's actions would also change the perception of the Force. The balance between the light and the dark side would shift, and the Jedi might have to reevaluate their teachings. It could lead to a more harmonious coexistence of the different Force - using groups in the long run.
Maybe Palpatine sees Ezra as a potential tool or apprentice at first. He tries to manipulate Ezra into joining him. Ezra, on the other hand, is conflicted because he might see some good in Palpatine's grand plans for the galaxy, but eventually realizes the cost of following the dark side. Their relationship would be a complex dance of manipulation and resistance.
Maybe some of the Jedi Council members. They were the ones who were constantly in conflict with Palpatine's plans, so they could be in the story to show the power struggle between the Jedi and Palpatine.