A possible fanfiction could involve a villain trying to steal the stones from Harry by targeting his bag. Since the bag is something Harry always has with him, it becomes a vulnerable point. The story could revolve around Harry's attempts to protect the stones in his bag, with the help of his friends, and in the process, they discover new magical properties of both the stones and the bag.
There might be a fanfiction where the stones are used to transform Harry's ordinary bag into a magical one. For example, it could become a bag that can hold an infinite amount of things or can teleport items directly into Harry's hands when he needs them. This would add a new and exciting element to his adventures, as he could use this new feature of the bag to outwit his enemies.
One interesting fanfiction could be about the magic stones having a special connection to Harry's bag. Maybe the bag has a hidden compartment only accessible when the stones are near. It could be a story where Harry discovers this connection while on a dangerous adventure in Hogwarts, and the stones' power helps protect the contents of the bag which might hold some crucial secrets or items.
There might be a fanfiction where the dragon familiar has a special bond with Harry that allows it to sense his emotions. So when Harry is in danger, the dragon comes to his rescue even without being summoned. It could add a whole new layer of adventure to the Harry Potter universe.
One possible fanfiction could be where Harry snaps his wand in a moment of extreme anger and despair after losing a dear friend. In this story, he then has to find a way to regain his magical abilities without his wand, perhaps through some ancient and forgotten magic. It could show his journey of self - discovery and growth as he copes with this new situation.
In some fanfictions, his other aunt might be a key figure in a hidden wizarding society. She could be part of a group that has been observing Harry from afar, waiting for the right moment to bring him into their fold and teach him things that Dumbledore or others haven't. For example, she might know ancient spells that can unlock hidden powers within Harry.
One interesting fanfiction could be where Harry has a surprise party organized by his friends at Hogwarts. They decorate the Gryffindor common room with floating candles and enchanted streamers. Another might be a story where Harry discovers a long - lost family heirloom on his birthday that has magical powers. And there could also be a fanfic in which Harry spends his birthday away from Hogwarts, in the Muggle world, and has to deal with some strange magical occurrences there.
I'm not sure of a specific one off the top of my head, but you could search on fanfiction.net. There are likely many there that involve the stones and the bag. Maybe look for ones with high ratings and lots of reviews. That's usually a good sign that it's an interesting read.
One great fanfiction could be where Harry and Neville team up to discover a hidden magic within Hogwarts. They might find a secret chamber that holds ancient spells and have to work together to unlock its mysteries. This could show their different strengths - Harry's courage and Neville's knowledge of plants and Herbology coming together in an exciting adventure.
One interesting 'Harry Potter' fanfiction could be where Harry is prone in a dangerous situation, like in a hidden chamber filled with dark magic traps. In this fanfic, his friends might have to figure out how to rescue him without setting off the traps.
One interesting aspect could be the unique crossovers. For example, integrating the Infinity Stones into the Harry Potter universe can lead to new magical abilities and power dynamics. Maybe a character uses an Infinity Stone to enhance their Patronus or to break a powerful dark magic spell. It also allows for creative interpretations of how the different Houses in Hogwarts would react to the presence of such powerful and foreign objects.
One interesting fanfiction could be about the Dursleys having a change of heart before Harry goes to Hogwarts. Maybe they start to see the magic in him in a different way and struggle with their newfound feelings of protectiveness. It could show a different side of the usually cruel Dursleys.
One popular fanfiction might be about the Dursleys' secret past that somehow ties them to the wizarding world in a more complex way. For example, perhaps there was a wizard in their family line long ago that they've been trying to hide. Another could be a story where the Dursleys have a change of heart much earlier than in the original series and start to embrace Harry's magical nature, leading to all sorts of comical and heartwarming situations as they try to understand the wizarding world. And there could be a fanfiction where the Dursleys are forced to face the consequences of their mistreatment of Harry in a more magical and extreme way, like being haunted by magical apparitions that represent Harry's pain.