Patrick Ness is great - really different and unusual. The Knife of Never Letting Go, A Monster Calls, More Than This. All good and all different.
The Girl of Ink and Stars and The Island at the End of Everything (both Kiran Millwood Hargrave) are beautifully written and poetic.
Moving towards adult books, Daphne du Maurier is great for younger teens, although the style can be a bit complex to mimic. Rebecca is the best one and Frenchman's Creek is the easiest.
Michelle Paver's Dark Matter is another lovely piece of writing and is a genuinely scary ghost story (the ghostly bit doesn't kick in until quite late in the book and is quite gruesome when it does come). Her books for younger readers eg Wolf Brother has me gripped at 41 so not to be sniffed at if not yet read.
The main thing is to tap into interests, even if these are spin-offs from quite ordinary things, eg if she is into the musical Hamilton there are quite a few YA romances out at the moment about Alexander and Eliza Hamilton, etc.
Miss Peregrine's Home for Peculiar Children is interesting, the sequels a bit less so.
Flight of a Starling by Lisa Heathfield is a little gem but very sad with a suicide theme.