Mushoku Tensei - Isekai Ittara Honki Dasu
Chapter 8 is out.
There isn't really anything that has a good amount of chapters out like those(excluding overlord).
Here are some others which have a few chapters out:
Yomigaeri no Maou(demon king is reincarnated into a human)
Sayonara Ryuusei Konnichiwa Jinsei(dragon is reincarnated into a human)
World Teacher(Old modern assassin is reincarnated into a magic world)
Mother of Learning(MT magic system + groundhog day)
Death march kara hajimaru isekai kyousoukyoku(programmer is transported to a fantasy mmo)
Tsuyokute New Saga(hero beats demon lord, gets send back to the past before shit went down)
Yuusha Party no Kawaii Ko ga Ita no de, Kokuhaku Shite(human reincarnates as strongest demon, falls for hero party's fem priest)