A few favorites: Tori Amos, Björk, Kimbra & Emilie Simon. Should get you started.
I second these! Kimbra is the only 'average' one here IMO and shes still pretty solid
The other 3 are amazing.
And yeah pretty much talk to Raven for any recommendations on this sort of music. He certainly aced it in my roulette!
A few more that aren't talked about much on the forum: Jo Hamilton, Joanna Newsom, Sarah McLachlan, Emiliana Torrini.