In a fanfiction, their relationship might start with a lot of tension. Thor, being the golden child, was always favored, which made Loki jealous. Hela, being older and more powerful, was banished. But a plot could be crafted where Loki discovers a way to bring Hela back. At first, Thor is against it, fearing she'll cause more destruction. But as they interact, they find that they have more in common than they thought, like their love for Asgard in their own ways, and they start to form a bond.
They could embark on a journey to find a lost Asgardian artifact. Thor's strength would be useful for any physical challenges they face, like fighting off monsters guarding the artifact. Loki's trickery could help them get past tricky traps and illusions. Hela, with her death - related powers, could deal with any undead or dark magic they encounter along the way.
In many comic storylines, Hela is depicted as a powerful foe, but Thor often holds his own and can match or surpass her strength depending on the circumstances.
Hela isn't Loki's daughter in the comic universe. Their characters have separate origins and roles. There's no established connection of that nature between them.
One great Loki x Hela fanfiction is 'A Meeting of Gods' which delves into their complex relationship. It shows how their different powers and personalities interact in a really interesting way. The author does a great job of creating a believable scenario where they have to team up against a common enemy.
Redemption is also a theme. Hela is often seen as a villain, and Loki has his own morally ambiguous actions. Fanfictions sometimes focus on one or both of them seeking redemption. They might help each other on this journey, like Loki guiding Hela to see a different path, or Hela teaching Loki about true power and its responsibilities.
One good Thor x Hela fanfiction could be 'Thor and Hela's Reconciliation'. It might explore how they overcome their differences after the events in the movies. Another could be 'A Different Path for Thor and Hela', which perhaps delves into an alternate universe where they have a more positive relationship. There's also 'Thor's Bond with Hela' that could focus on the development of a unique connection between them.