Is there anyone here with a list of JOSEI OR SHOUJO being an older female with a younger g...

Kimi wa Petto

Thanks need more ヾ(☆▽☆) I’m looking for a certain manga that have an older female OL and a HS boy

Dear Mine - is my fav Not HS boy, I think its ES boy x MS/HS girl

You can search "Older Female Younger Male" as a tag on Baka Manga. Here's the josei result: https://www.mangaupdates.com/series.html?category=Older+Female+Younger+Male&genre=Josei&perpage=50

Other than that, I second Kimi wa Petto. You'll also probably like A Bride's Story, a personal favourite of mine with an age gap similar to My Boy's.

Others I can remember off the top of my head:
* Miageru to Kimi wa
* Love at 14 (Secondary couple)
* Dokuhime

(⌒▽⌒) arigatou gozaimasu ... I will look it up