Yes, there are quite a few. You can find some on popular fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Star Wars Rebels Ahsoka Kanan romance' and you'll get a list of stories to explore.
Common themes include their shared struggle against the Empire. In these fanfictions, their fight against the common enemy can bring them closer romantically. Also, the theme of mentorship sometimes plays a role, as they both have different levels of experience with the Force and can learn from each other in that regard. Their relationship is often depicted as evolving from comradeship to something more romantic over time.
One great Kanan x Ezra fanfiction is 'The Bond Beyond the Force'. It beautifully explores their master - apprentice relationship. It shows how Ezra grows under Kanan's guidance and the deep emotional connection they develop. It has some really touching moments, like when they face a difficult trial together and have to rely on each other's strengths.
In 'Star Wars Rebels', Kanan's story is quite interesting. He was a Padawan when the Jedi Purge happened. Throughout the series, he not only trains Ezra but also forms a strong bond with the rest of the rebel crew. His journey includes rediscovering his Jedi identity and using his skills to fight the oppressive Galactic Empire. He also has a complex relationship with Hera, which adds depth to his character.
There's 'The Adventures of Kanan and Ezra: Untold Tales'. This one is full of exciting escapades. It's like filling in the gaps between the episodes of the show. It has a lot of banter between Kanan and Ezra, which is really fun to read. It also shows how they rely on each other in different situations, whether it's facing a Sith or just getting out of a tricky diplomatic situation on some planet.
They could find themselves on a desolate planet filled with strange and terrifying creatures. The planet has an eerie atmosphere that makes them constantly on edge. When they are attacked by a horde of these creatures that seem impervious to their usual attacks, they are filled with fear. But they must overcome it to survive and find a way off the planet.
I really like the fanfiction 'Hera and Kanan: The Unspoken Alliance'. In this story, the author beautifully portrays the chemistry between Hera and Kanan. It's full of action scenes where they fight side by side, but also tender moments that show their growing affection. Another interesting piece is 'Kanan's Promise to Hera'. It's set during a particularly dangerous mission, and Kanan makes a promise to Hera that he'll always be there for her. This adds a layer of depth to their relationship. Then there's 'The Path of Hera and Kanan' which follows their journey through different planets and how they support each other in every step.
In some fanfictions, Kanan might die heroically in a battle against the Empire. He could sacrifice himself to save his friends or to protect an important cause. For example, he might hold off a large group of stormtroopers while his comrades escape.
Well, in a fanfiction where Ezra is trained by Ahsoka, it might start with Ahsoka recognizing Ezra's potential. Maybe she sees his raw talent with the Force and decides to take him under her wing. This training could lead to Ezra having a different perspective on the Force, perhaps more in line with Ahsoka's own beliefs which were shaped by her experiences with Anakin. It could also change the way he approaches battles and his role within the Rebellion.
One great 'Ahsoka Star Wars Rebels' fanfiction is 'Ahsoka's New Path'. It delves into Ahsoka's life after leaving the Jedi Order and her experiences in the Rebellion. It shows her growth and how she uses her skills to help the rebels in unique ways.