Feed My Need for Crossovers

I love 'em big time. I just like seeing how authors blend fandoms. I'd like them mainly to be casefics, ot just random meetings unless you really love them.

Looking for:
Supernatural - I've read a bunch but what to know what you like.
Once Upon a Time
Castle
Hawaii Five-0
Bones
NCIS
NCIS: LA
White Collar
Revenge
Big Bang Theory
The Mentalist
Grimm
Fringe
Eureka
Doctor Who
Torchwood
The Listener
Jonathan Creek
The Sentinel
John Doe
The Pretender

I really could keep going. If there's a crossover with a show not listed that doesn't need a knowledge of the other show, feel free to include it.