Yes, there might be. Fanfic writers often explore various aspects of the 'Hunter x Hunter' universe, including creating stories around the cure for unique poisons like the 'Poor Man's Rose' poison. You can try searching on fanfic platforms like Archive of Our Own or Fanfiction.net.
The 'hunter x hunter poor man's rose cure fanfic' might be centered around the concept of using the poor man's rose, which is probably a unique element in the Hunter x Hunter world, to create a cure for a particular ailment or a curse. It could involve characters exploring the origin of this rose, its properties, and how to harness its power for the cure. It might also have elements of adventure as the characters search for the necessary components or knowledge related to this cure.
Since it's a fan - made story, the main characters could be new characters created by the author. However, it's also very likely that it involves some of the well - known characters from Hunter x Hunter. Maybe Gon and his friends are called upon to help a sick village and they find out about the poor man's rose as a possible cure. So Gon, Killua, and Leorio could be the main characters in this fanfic's story about the cure.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.