As the story progresses, their relationship could become more complex. Harry might become a father figure to Tom, teaching him right from wrong. Tom, on the other hand, could start to see Harry as someone he can rely on, but also struggle with his own inner demons that might pull him away from Harry's influence.
One common theme is redemption. Since Tom Riddle becomes Voldemort in the original story, these fics often explore the idea of whether he can be redeemed with Harry's help. Another theme is the power of family. Harry, having grown up without a proper family for a long time, tries to create a loving family for Tom. And the theme of changing destiny also runs through. It's about whether they can change the dark future that was set for Tom in the original story.
One possible plotline could be that Harry, having seen the destruction Tom Riddle caused as Voldemort, decides to take young Tom under his wing to prevent him from going down that dark path. He could introduce Tom to the love and friendship he never had, like the friendships Harry formed at Hogwarts. This new environment and positive influence might change Tom's view of the world.
Another plot point could be the way Harry tries to prevent Tom from turning into Voldemort. He might use his own experiences of fighting Voldemort to guide Tom away from the dark path. Maybe he shows Tom the consequences of dark magic through his memories, which could be a very emotional and impactful moment in the fanfiction.
Perhaps in the fanfiction, Harry adopts Tom Riddle when he's still a young boy at the orphanage. Harry then uses his own experiences of growing up without parents to bond with Tom. He teaches Tom about magic in a different way than Dumbledore did, focusing on the positive aspects of magic for good. This could lead to Tom not becoming the evil Voldemort we know.
Harry would likely use his own experiences of facing inner darkness. He could talk to Tom about his struggles with the part of Voldemort that was in him. By sharing his own story, he hopes to make Tom understand that he has a choice and doesn't have to give in to any dark desires.
At first, it might be rocky. Tom would be suspicious of Harry's intentions. But as Harry shows him genuine care, Tom would start to open up. Eventually, they could become like family, with Tom looking up to Harry as a role model.
There's also 'Redemption's Chance'. This fanfic focuses on Harry taking Tom under his wing. It shows Harry using his own experiences of loss and struggle to connect with Tom. The story is filled with heart - warming moments as Harry tries to give Tom a loving home environment. It also has some great magical elements and battles that are unique to this new take on the Harry Potter universe.
One possibility is that Harry, having seen the dark path Tom Riddle took, decides to take him in early. He might teach Tom about love and friendship, things he lacked growing up. Harry could introduce Tom to the wizarding world in a more positive light, showing him the joys of Hogwarts and the value of good relationships, thus preventing him from turning into Voldemort.
One common theme is redemption. Since Tom Riddle later becomes Voldemort, the idea of fem Harry being able to change his path and redeem him is often explored. It gives a sense of hope that even the darkest of characters can be saved.