It could change Hermione's relationship with her parents. They might be angry at her for what she did to their memories in the first place. Or, they could be so proud of her for being a powerful witch that they become more involved in the wizarding world, which would be a big change for all of them.
Her parents might be in danger. Since Voldemort was after her, now that they remember her, they could become targets. The Death Eaters could use them to get to Hermione.
I remember reading a fanfic called 'Restoring What Was Lost'. It delved deep into Hermione's emotional turmoil while attempting to restore her parents' memories. The author beautifully described her fears of what would happen if it went wrong. It was a really unique take on the concept as it also incorporated some elements of Hermione's research in the Hogwarts library to find the right solution.
Often, there's a countdown or a time limit involved. Maybe there's a magical condition that if not met within a certain time, her parents' memories will be lost forever. This adds a sense of urgency to the story. Also, the use of Hermione's own guilt and determination as a driving force for her to keep trying in the face of multiple failures is quite common.
Well, 'Hermione's Memory Quest' is also a fanfic you should check out. It not only focuses on her restoring their memories but also shows how her friends, especially Harry and Ron, support her through the whole process. It gives a great look at the friendship dynamics while dealing with this complex magical situation.
One way could be through the use of time - turning. If she could go back in time to before her parents' memories were altered, she could prevent it from happening. However, this would be extremely dangerous and against the laws of time in the wizarding world. But in fanfiction, the rules can be bent. Hermione is known for her intelligence and determination, so she might be willing to take the risk.
She might become more distrustful. After being betrayed, it's natural for her to question the motives of those around her, even her closest friends.
One interesting aspect of Hermione Granger and her parents in fanfiction could be exploring how their Muggle background affects Hermione's Hogwarts experience. In some fanfictions, her parents might be more involved in the wizarding world than in the original series, which adds a new dimension to Hermione's story.
If Hermione's parents find out in fanfiction, it could also have an impact on her friendships. For example, they might be overly cautious about who she hangs out with at Hogwarts. They could demand to meet her friends' families, which would be really awkward for some of her wizard friends. Also, the wizarding world might view Hermione differently if her muggle parents are suddenly so involved. There could be those who are suspicious of them, while others might see it as a chance to bridge the gap between the two worlds.
Voldemort may also try to extract information from her. Given Hermione's vast knowledge, he might think she knows secrets about the Order of Phoenix or Dumbledore's plans. He could use various dark magic methods to force her to talk.
One popular theme is family reconciliation. Since Hermione is often so involved in the wizarding world, fanfictions might explore how she reconnects with her Muggle parents after a long time. Another theme is the discovery of Hermione's family's hidden magical heritage. It could be that there are some secrets about the Granger family that are revealed in the fanfiction.
One great Hermione and her parents fanfiction is 'The Granger Family Reunion'. It beautifully explores the relationship between Hermione and her parents in a post - war scenario. The story delves deep into how they cope with the changes in Hermione's life due to her experiences at Hogwarts. Another interesting one is 'Hermione's Muggle Roots', which focuses on how Hermione's parents influenced her values and her journey in the wizarding world.