I'm trying to find if there are any other words or phrases that have a similar meaning to Little Black Book. More looking along the lines of a word or phrase to mean a list or book where you keep important information, but usually about other people.
Little Black Book:
n. a book containing the names and addresses of acquaintances who are potential dates, usually put together by men.
Am I in your little black book, or can you already tell that I wouldn't go out with you?
(McGraw-Hill's Dictionary of American Slang and Colloquial Expressions)