Recently we have made an effort to tag up the content we have in the content library. We hope it is now a lot easier to find the kind of stuff you are looking for. But, what is it you are looking for? What kind of content is it that you would really like to use? We know that the library is by no means complete, but is there anything specific you would like to see there?
You can of course upload whatever you are missing yourself, as long as it is your material, or have a Creative Commons Attribution license, but we would also like to help if we can.