Go under any other ones that you've read and checkout the tags, site recommendations and even other peoples' personal list.
Not northern duke perse but royalty
https://www.mangago.me/read-manga/sweetie_sweetie_sweetie/
https://www.mangago.me/read-manga/the_rogue_prince_is_secretly_an_omega/
https://www.mangago.me/read-manga/how_the_sidekick_prince_lives_again/
https://www.mangago.me/read-manga/in_the_hall_of_the_mountain_king/
https://www.mangago.me/read-manga/the_moon_painting_alchemist/
https://www.mangago.me/read-manga/hey_prince/
https://www.mangago.me/read-manga/regas/
https://www.mangago.me/read-manga/smyrna_capri/
https://www.mangago.me/read-manga/willow_love_story/ modern
https://www.mangago.me/read-manga/winterfield/
Been addicted to plots on duke of the north lately please recommend me some!! thank you >3<