You can also check out Wattpad. It has a variety of fanfiction including some for HxH. While it has a broader range of content including non - fan - based stories, if you search specifically for HxH fanfiction, you might come across some interesting reads. However, the quality can vary more compared to AO3 and FanFiction.net.
One great 'HxH Illumi x Reader' story could be about the reader being a new hunter and Illumi taking an unexpected interest in them. Maybe he's intrigued by their unique nen ability or their fearless attitude towards the dangerous tasks hunters face.
Antique songs were a very unique music style that usually combined elements of traditional Chinese music and modern pop music. Here are some songs that I think are very good:
1 Blue and White Porcelain-Jay Chou
2 "Sword and Heart"-Tan Weiwei
3 "Shuidiao Ge Tou"-Su Shi
Big Fish-Zhou Shen
Song of Everlasting Regret-Bai Juyi
6 "Red Maiden"-Li Qingzhao
7 "A Thousand Miles Away"-Jay Chou
8 "Once in a Thousand Years"-Jay Chou
9 "Nocturne"-Jay Chou
Blue and White Porcelain Opening Song-Ancient Wind Team
These songs all had a strong Chinese style, beautiful melodies, and deep emotions. They were very suitable to interpret the plot of an ancient novel. Of course, different people have different preferences for ancient songs. You can choose a song that suits you according to your taste.
I don't think so. There haven't been any official announcements or indications that the HxH manga will continue. But you never know, maybe there'll be a surprise in the future.