there are so many, but here are my faves:
https://www.mangago.zone/read-manga/ranker_who_lives_a_second_time/
https://www.mangago.zone/read-manga/omniscient_reader_s_viewpoint/
https://www.mangago.zone/read-manga/tomb_raider_king/
https://www.mangago.zone/read-manga/return_of_the_sss_class_ranker/
https://www.mangago.zone/read-manga/kill_the_hero/
https://www.mangago.zone/read-manga/the_legendary_moonlight_sculptor/
https://www.mangago.zone/read-manga/solo_max_level_newbie/
https://www.mangago.zone/read-manga/otherworldly_sword_king_s_survival_records/
Random background character stories:
https://www.mangago.zone/read-manga/solo_leveling_arise/
Solo leveling but his son:
https://www.mangago.zone/read-manga/solo_leveling_ragnarok/
Havent read them yet but they're literally solo leveling so i figured its a valid addition
To a new life
Any manhwa recs like solo Leveling??? Pls im desperatee