Historical / Isekai / reincarnate BL I:
https://www.mangago.me/home/mangalist/835803/
Historical / Isekai / reincarnate BL III:
https://www.mangago.me/home/mangalist/2728331/
I've always hated Harem and Ecchi along with the typical Weak Ukes in manga.
For those who hate those tropes this list contains:
Smart Male Leads
♧Strong Male Leads
♤Strong Ukes
♧Strong Semes
♤Healthy Relationships
♧No Ecchi
♤No Harem
♧No Oppais
◇◇◇◇◇◇◇◇◇《Enjoy》 ~♡♡♡♡♡♡♡♡♡
PS: I'll try to give a review for ever manga that I possibly can on this list. Some of them may have only plot summaries as of now.
This is just a list of manhwa/manga which has main character/s who gained a second life in the modern world setup.
Main Characters: Reincarnated/Second Life
Settings: Modern Society
The list is in no particular order.
Feel free to suggest anything in the comment section.