One idea could be a story where Anakin and Ahsoka are reunited after a long time apart. Maybe Anakin has been on a secret mission and Ahsoka has been exploring new parts of the galaxy. When they meet again, they have to work together to face a new threat that is endangering the Jedi Order.
They could also be portrayed as friends. After all, they've been through a lot together. They share a bond that goes beyond the typical master - apprentice relationship. In some fanfictions, they might have casual conversations, joke around, and support each other like true friends do.
One common theme is mentorship. Their master - apprentice relationship is often explored in depth. Another is loyalty, as they were very loyal to each other during the Clone Wars.
There are many good ones. Fanfiction gives a chance to expand on their relationship in ways that the official canon might not have fully explored. For example, some stories might explore what could have happened if certain events in the Clone Wars had turned out differently regarding their relationship, or they might focus on their unspoken emotions and how they could have developed further.
One positive aspect is that it can explore their complex relationship in a more family - like or platonic way. For example, it can show how Anakin's mentorship influenced Ahsoka's growth as a Jedi. It can also focus on their shared experiences in the Clone Wars, like how they strategized together in battles.
Archive of Our Own (AO3) also has a wide selection. Just use the search filters to exclude any mature or inappropriate tags. You might find some really interesting fics that explore their adventures together, their growth as characters in relation to each other, and the impact they have on one another's lives in a family - like or friendship - based context.
One great fanfic could be 'The Bond Beyond Padawanship'. It delves into their relationship as master and apprentice, exploring how they trained together and the mutual respect they had. It shows Anakin's unorthodox teaching methods and Ahsoka's eagerness to learn.
The theme of family also shows up a lot. Since they have a very close bond, it's like a family connection. Some fanfictions explore how they are there for each other like family members, through thick and thin.
Often, their relationship develops through shared trials. Fanfics might show them facing a powerful Sith lord together. During this, they learn to trust each other completely. Anakin might even start to see Ahsoka as a true equal rather than just his apprentice. This is a significant shift in their dynamic.
I like 'Journey with Anakin and Ahsoka'. In this fanfiction, they go on a journey that takes them to different planets. Along the way, they have to rely on each other more than ever. It's a story that really showcases their growth both as individuals and in their relationship with each other.