Harry Potter himself is very common. Given his connection to the Deathly Hallows, it makes sense that he would be involved in stories about the Resurrection Stone. Hermione Granger is also often included, as her intelligence could be used to figure out the secrets or consequences of the Stone. Ron Weasley might be there too, providing support and his own brand of humor. Dumbledore also frequently shows up, either as a guiding figure or as someone whose past actions related to the Stone are explored further.
Voldemort is often a key character in such fanfictions. His dark nature and thirst for power can easily lead to situations of carnage. He might be leading his Death Eaters in attacks on Hogwarts or the wizarding community at large.
Harry Potter himself is often a central character in such fanfiction. Since he's the main character in the original series, many fanfic authors like to explore how he deals with new or different curses. Hermione Granger is also common as she's very knowledgeable about magic, so she might be involved in researching curses or finding ways to break them.
Another set of characters could be Harry, Ginny, and Luna. Harry has a relationship with Ginny in the original series, but Luna's unique personality and her connection with Harry in some parts of the story can be explored in a love triangle scenario in fanfiction.
There are also often new or side characters created specifically for the fanfiction. These could be villains who oppose Naruto's resurrection or allies who help him adjust to the new world he wakes up in. For instance, a mysterious sage who has knowledge about the resurrection process and guides Naruto through the initial stages of his return.
Obviously, Harry Potter himself is very common. He has a strong connection to the story's main events, so it makes sense for him to be involved in time - travel scenarios. Hermione Granger is also often included. Her intelligence and knowledge of magic, especially time - related spells like the Time - Turner, make her a key figure. Ron Weasley usually tags along as well, being Harry's best friend and part of the main trio.
Hermione Granger is also a common character. Given her love for knowledge and her skills in magic, she would likely be researching the best spells and magical theories to make the terraforming successful. She might be the one to find ancient spells that are crucial for the process.
In many expelled Harry Potter fanfictions, the Weasley family as a whole gets involved. Molly Weasley would be worried sick about Harry and would be cooking up plans to get him back. Fred and George might use their prank - making skills to expose the truth behind the expulsion. Ginny, being Harry's love interest in the original series, would be actively involved in trying to clear his name. And don't forget about the Hogwarts professors. McGonagall would probably be torn between following the rules and believing in Harry.
Harry Potter himself is often a central character. He might be shopping for new school supplies at Flourish and Blotts or looking for a new broomstick at Quality Quidditch Supplies. His friends, like Hermione and Ron, usually accompany him. Hermione might be more interested in books and rare magical artifacts, while Ron would be eyeing the latest Quidditch gear.
Mrs. Weasley is a very likely character. She's an expert at cooking and baking in the normal wizarding world, so in fanfiction about magical bakes, she could be teaching the younger characters how to make special bakes. Hagrid might also be involved. He could bring in some really strange ingredients from the Forbidden Forest, like giant acorns, to be used in the bakes.
Hermione Granger is often involved. In some fanfictions, she discovers hidden conspiracies within the Hogwarts library. For example, she might find a book that reveals a plot by some of the older pure - blood families to keep certain magical knowledge from half - bloods and Muggle - borns.