The Seymour Duncan website alone has probably more free wiring diagrams you'll ever need!
I've found it pretty easy to just google what I'm looking for and get sufficient results. EG. Type in "Bridge humbucker 2 single coils, with phase switch." You have to a little bit of digging, but you'll find what you need. Sometimes a google image search will yield a lot in the way of diagrams.
That's what I've been doing, but I'd like something a little more in depth and organized for my library. For instance, for Teles alone, there have been numerous different wiring diagrams that Fender has used through the years, and a chronological review of each with reasons for changes would be nice to have. Same for other guitars as well.
I know there were dedicated books about Strats and Teles that went over an reprinted factory wiring diagrams. I got an early edition of a Strat book, that had the wiring diagram of my 1982 'The Strat' which is about as convoluted as it gets.