The manga of Hunter x Hunter has no clear-cut ending. The story has been on hiatus for a long time, leaving fans waiting and speculating about its conclusion.
The ending of Hunter x Hunter in the manga is quite complex and somewhat open-ended. The story progresses through various arcs and plotlines, but it doesn't have a neatly wrapped-up conclusion.
They could watch the development of new nen abilities. Maybe some characters watch as Ging discovers new techniques or as Hisoka creates his unique and deadly attacks. Also, in fanfiction, they might watch events related to the Phantom Troupe. For instance, the characters could be observing how the Troupe members interact with each other during a heist or when they are facing off against hunters.
You can start by looking on fanfic websites like Archive of Our Own (AO3). It has a large collection of Hunter x Hunter fanfics and you can search specifically for ones that involve Cheadle and Pariston. Just type in their names in the search bar and you'll get a list of relevant stories.
You can try online bookstores like Amazon. They usually have a wide range of books available, including the 'hunter x hunter novel' if it's in print and distributed in your region.
The Hunter x Hunter anime ends approximately around a specific chapter in the manga. But it's a bit tricky to pinpoint exactly as it depends on the version and adaptations.
The manga of Hunter x Hunter left off at a rather cliffhanger point. The story was ongoing but the author went on hiatus and it's still unclear when or if it will resume.