
https://www.mangago.zone/read-manga/npcs_can_save_the_world_too/
This one is ok. Would've liked more chapters to flesh out the story and world better, but overall it isn't bad.

https://www.mangago.zone/tag/yaoi%20harem/ Look under this tag

I realized the first link was wrong haha it was supposed to be this one:
https://www.mangago.zone/read-manga/bl_game_no_shujinkou_no_otouto_de_aru_koto_ni_ki_ga_tsukimashita/
I looked everywhere here in Mangago and I found few. fewer than my fingers actually.
despite Harem being so popular I'm surprised it's almost none existent in the BL Manga world.
the only ones that piqued my attention was these two and the other one was unfortunately discontinued.
https://www.mangago.zone/read-manga/tenjou_no_shita_ni_koi/
https://www.mangago.zone/read-manga/bokura_to_usagi_no_koi_wa_sensou/
if you know more please let me know.