It's a pian in the ass, more than rare, to get, but there are the 3 sets of journal books from Khaldun, that are a good addition to any library.
They drop from Lysander (6 books), Grimmoch (9 books) and Tavara (13 books) and come in both purple book and red book varieties, making putting together matching sets even more difficult.
I sold several sets of these for 500k + on Lake Austin recently, and given that most other shards have more active PK in Khaldun, they should be even more valuable and difficult to get on other shards.