One common theme is the relationship between Cormoran and Robin. Many fan fictions explore their partnership further, whether it's a budding romance or a deeper platonic bond.
There's a fan fiction called 'Strike and Robin's New Adventure' that takes the duo on a case outside of London. It's full of mystery and great dialogue between the two main characters, just like in the original books.
Yes, there will be. J.K. Rowling has been quite engaged with this series and given its popularity, it's very likely she'll continue writing more Cormoran Strike novels.
As of now, there is no definite information regarding a new Cormoran Strike novel. The previous novels in the series have been well - received, which might suggest that there could be more in the future. But we have to consider that the author, J.K. Rowling, is involved in multiple projects. She might be exploring new ideas or working on other stories. The publishing world also plays a role. If the publishers see a high demand for a new Cormoran Strike novel and if J.K. Rowling has the time and inspiration, then it's very likely that we will see a new one. But until then, we can only wait and hope.