Below are a few sites I've came across in my past time of being on the web, some already we know about, and some you probably have seen before. However just thought it would be nice to have some sort of list with all of these resources together;
Icons:
Patterns:
Stock Photography:
Fonts:
Colour Schemes:
There's just a few. I'll continue to search these forums for resources people have posted to compile this list even further into more categories.