This manga is mostly comedic from what I can remember, but it does have it's serious moments and has some great character development in regard to its female lead. The Yandere in this is the pretty blue haired boy who cross-dresses as a girl. His possessiveness and obsession do take a while to show but when they do it's really good.
These are all the yandere moments in Cherry Boy, That Girl up to Chapter 50, as that is how far I have read up to in my current re-read. I will update this as I get further in the story.
I'm not a fan of this one as it is a very stereotypical, by the numbers possessive ML shoujo manga. Not much to say about this one as it's short (only 4 chapters), but if you like that kind of manga you should give this a look.
While the yandere in this is really good and very manipulative, I'm a bit hesitant to recommend this due to the fact that it hasn't been updated since December of last year. A high quality yandere though. (The yandere is the black haired guy on the front cover)
While I have personally never been able to get into this manga, a lot of other male yandere lists on here recommend this. The male yandere is the brown haired second male lead. the white haired male lead is also kinda yandere. Definitely read this and form your own opinion though.
I haven't read this one yet but have heard that the yandere in this is the male lead and he is a high quality yandere. Be warned though, a lot of the comments on this manhwa complain about how the female lead can be quite annoying and will have you feeling a lot of second hand embarrassment. I don't no how true these comments are but it has put me off from reading it. If anyone does end up reading leave a comment telling me your opinion!
Both the ML and FL in this are kinda screwed up but the ML is 100% yandere.
This is a really long read and Yoo Jung (the black haired ML) is a more subtle and realistic kind of yandere. This has like 300 chapters, is completed and just a very well written webtoon in general.
The ML and FL are yandere for each other and aren't really that likable, which does make this hard to read sometimes. For me at least, the intensity of the ML's obsession was enough to keep me reading.
Cherry Boy, That Girl