Kaguya otsutsuki is often a very popular character. Since she was the progenitor of the otsutsuki in the Naruto canon, fanfictions like to explore more about her backstory and her relationship with other characters. Another popular one is Momoshiki otsutsuki. His powerful abilities and his encounter with Naruto in the series make him a great character to expand on in fanfiction.
Kaguya Otsutsuki is often a central character. She has a significant role in the original Naruto lore related to the Otsutsuki, and in fanfictions, her backstory might be further elaborated or her powers could be enhanced or explored in different ways.
Momoshiki Otsutsuki is also quite popular. His powerful abilities and his role as a major antagonist in the Boruto series give a lot of material for fanfic writers. They can expand on his backstory, or create alternate scenarios where he has different interactions with the main characters.
Kaguya Otsutsuki is often very popular. As the progenitor of chakra, she has a lot of mystery surrounding her, and fanfiction writers like to explore her backstory further, perhaps giving her more complex motives for her actions in the original story.
Indra and Asura are also characters that are frequently paired with Hagoromo in fanfiction. These pairings often explore the family dynamics more closely, such as Hagoromo teaching them new skills or them helping Hagoromo in some way that was not shown in the original series.
Saitama from One Punch Man would be an interesting pair. Saitama's simple yet overpowered nature could create an interesting dynamic with Hagoromo's complex and ancient powers.
The names of the 12 Clan Masters might be different, but the common records included the East Clan Master Lan Caihe, the South Clan Master Ge Xuan, the West Clan Master Hong Lian, the North Clan Master Chi Lian, and the Middle Clan Master Grand Supreme Elder. In addition, the members of the 12 masters in " Bad People " included Li Maozhen, Fresh Ginseng, the 11th master, and Li Xingyun's uncle. In addition, there was another saying that Master Huijue was the chief master of the twelve caves. However, because the search results provided did not provide a definite answer, it was impossible to determine the specific candidate for the 12th master.
The names of the 12 clan masters might be different. According to a common record, the 12 Clan Masters were: East Clan Master Lan Caihe, South Clan Master Ge Xuan, West Clan Master Red Lotus Cult Master, North Clan Master Chi Lian, and Middle Clan Master Grand Supreme Elder. Other than that, there were also other versions that mentioned the masters of the other guilds, such as Li Meng, the Eleventh Master, Xian Shen, Chi Meng, Chi Li, You Chuan, Li Maozhen, Sheng Tong, and so on. However, the exact name list of the guild masters might differ according to different legends and versions.