I come up with the following list of the most powerful eunuchs (or castrated men) in the entire Jin Yong world :
1 - Huang Shang (Creator of 9 - Yin, destroyed the Ming Cult, single-handedly defeated all his enemies)
2 - Dong Fang Bu Bai (Chief of the Demon Cult, Practioner of KHBD, defeated by the combined force of LHC, RWX, RYY and XWT)
3 - Lin YuanDu (Lin PingZhi's Great Grandfather, original practioner of PXJF and the founder of the Escort House)
4 - Yue Bu Qun (Leader of Hua Shan Sword School, later castrated himself to practice PXJF, defeated ZLC)
5 - Lin PingZhi (Son of Lin Zhennan, cheated by his teacher, castrated himself to practice PXJF, destroyed YCH and MGF)
6 - Hao Da Fu (The elder Eunuch killed by Wei Xiao Bao during the confrontation with Empress Dowager)
7 - Wei Xiao Bao (If mouth could kill)
Did I miss any other powerful eunuchs ?