I think any List of Best X creates arguments and people saying 'You listed that rubbish?' That's what lists like this are for.
I have no problem with commenters stating strong opinions, except for my usual annoyance with people who don't agree with me.
I found a great book called 'Slang Through the Ages' by Jonathon Green. It's basically a thesaurus of historical slang, and had lots of great old uses.
I have no formal training as a writer at all, not even a single English class in college. However, my adult books are all science fiction, which has some similarities to YA.