Photoshop Layer styles
Also if you have some good layer stlyes and is willing to share then this is the place!
Go to the adobe website, where you'll find a plethora of add-ons/files etc. that will help you immensly.
It's a great place to get ideas & resources too. 
http://share.studio.adobe.com/axBrowseProduct.asp?p=2
At my link above, you'll find over 1000 styles which are all able to be dropped into the 'styles' folder in Photoshop. Many/most of them have thumbnails so you can decide whether they are the ones you want or not. Many have also been rated for usability etc, which helps in your decision.
So as not to bloat PS too much, I usually keep my styles & add-on's in a separate folder outside of PS ~and access them as necessary.
You do need to make sure whether they are compatible with your version of PS. Though most of them are labeled as to which versions they work with.
Also, you need to be signed up to download anything from there ...but it's free.
If you have PS open when you drop the files into their relevant folders, you'll need to close out and re-start PS for them to be acessible.
I also use Jaramia's method described above, if I come up with a particularly interesting style I want to keep when playing around with PS. 
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