FanFiction.net also has time - travel Harry Potter fanfictions. Some might focus on Hermione using a time - turner in a more creative way than in the original books. You can read the summaries and reviews of these stories to figure out which ones are worth reading. There are stories that explore the consequences of changing the past and how it affects the future of the wizarding world, which adds an extra layer of intrigue to the fanfiction.
A great fanfiction idea could be that James Potter time - travels during a crucial battle in the wizarding world. He travels back to a time when the dark forces were just starting to rise. With his future knowledge, he could start preparing the wizarding community earlier. He could train young wizards and witches in advanced defensive magic, and try to change the course of history so that the big battle he left behind would have a different, more positive outcome.
One possible fanfiction idea could be that a character discovers a time - traveling device while exploring the Chamber of Secrets where the Basilisk once lurked. They accidentally travel back in time to the era when the Basilisk was first created or when Salazar Slytherin was alive. This could lead to all sorts of adventures, like trying to prevent the Basilisk from being created or changing the course of Hogwarts' history regarding the Chamber.
One possible fanfiction could involve Bellatrix going back in time to try and change the outcome of the Battle of Hogwarts in her favor. Maybe she uses time - turners or some dark magic to travel back. She could attempt to kill Harry Potter as a baby before he even becomes a threat.
AO3 is probably the best place. There are various filters you can use. For example, you can sort the stories by popularity, kudos received, or date updated. Another option is Wattpad. Although it has a more diverse range of stories in terms of quality, you can still find some really good Harry Potter time - travel fanfictions if you dig a bit. Some Tumblr blogs also recommend and share great Harry Potter time - travel fanfictions.
One great fanfiction could be where Sirius Black travels back in time to prevent his own imprisonment in Azkaban. He might use his knowledge of the future to avoid being framed by Peter Pettigrew. This could change the entire course of the story, as Harry would then have a more stable and present godfather figure in his life from an earlier stage.
One interesting Slytherin time - travel fanfiction could be about a Slytherin student who discovers a time - turner hidden in the Slytherin common room. They use it to go back in time to try and change the way Slytherin is perceived in the wizarding world. Maybe they go back to the time of Salazar Slytherin himself and learn the true intentions behind his actions, which were perhaps misinterpreted over the years.
One possible fanfiction could be that Draco, after realizing the error of his ways, uses a time - turning device to go back in time. He teams up with Harry Potter to prevent certain dark events from occurring in the wizarding world. They might work together to stop Voldemort's rise to power earlier, changing the fate of many characters.
I'm not entirely sure. Fanfiction can cover a huge range of ideas, and while time travel in Harry Potter is a common theme, and Orochimaru is a well - known character from Naruto. The combination seems a bit out there. But, if you search on some major fanfiction platforms like Archive of Our Own or FanFiction.net, you might be able to find out for sure if such a fanfiction exists.
Another option is to ask in Harry Potter - related forums or groups on social media. There are many passionate fans out there who might be able to recommend some great vampire Harry Potter time travel fanfictions that they have read. They could also give you insights on the quality and uniqueness of different stories.
You can start by looking on fanfiction websites like Fanfiction.net or Archive of Our Own. Use the search function and type in 'Harry Potter time travel'. Then read the summaries and reviews to see which ones seem interesting.