I have been waiting for a thread like this,
As an aside, there are so many creepy undertones in a lot of her books, specifically around dads and the teenage friends of their daughters (specifically the dad in Vicky Angel - at one point he picks up a photo of Vicky "Like he's going to kiss it" and Jade mentions how uncomfortable it makes her. Ellie's dad in the girls series has a strange fixation with one of her friends), I think someone has also mentioned the relationship in Midnight between Violet and her brother.
I adored JW as a child, but looking back on her books some of them were not child-friendly. I think most have already been mentioned but here are the main things that stick in my mind from those books.
Vicky Angel - Not only is there the tragedy of her friend but her mum is cheating on her dad with a married man and Jade finds out about it.
Girls series - One of them gets catfished online by a much older man, one is sexually assaulted by her boyfriend and another develops an eating disorder. As a child, it was pretty much an instruction manual on how to lose weight, it never quite sat right with me that there were no resources at the end of the book for young girls who may have been struggling.
The Longest Whale song - has a moment where the main character is pretending to be a whale at her school swimming lesson (?) and everyone assumes she was trying to drown herself
The worst thing about my sister - actually quite tame as JW books go, however, there is a scene where the two sisters are arguing and one kicks the other off a bunk bed ladder and she falls (but is ok by the end of the book if I remember rightly)
Little Darlings - Two girls who are half-sisters and the daughter of an ageing rock star. The dad runs off with a 19 (?) year old, one lives on an estate in Manchester and her single mum has suspected cancer so is desperate for her daughter to meet her dad so she'll be looked after. The dad is also kind of emotionally abusive.
Kiss - Main character is in love with her friend, who is gay. He collects glass and after he is outed at school he smashes his entire glass collection and ends up in hospital. She also makes friends with one of the popular girls who sends a nude to someone and it gets leaked...I don't remember what the outcome of that was but it was pretty traumatic.
Most of the other books have been explained but yeah, some of these I haven't read but have seen the adaptations which have stuck with me (DUSTBIN BABY)