I found this site a couple of days ago;
http://www.colourlovers.com/browseThey have an incredible collection of patterns and palettes.
The patterns are available as a gray-scale template (5 levels max) and as colored patterns in a variety of color schemes.
If you want to save the patterns, the trick is to click on the sample pattern block so it expands to a larger block, then right click to "View background image" (Firefox). That will give you a single block of the pattern which you can then save. Duh! Just click "preview" and it will open a single block of the pattern in a new tab. You can also download pattern-filled images in a variety of sizes.
The palettes are limited to 5 colors, but there are some very nice color combinations. You can download the palettes as GIMP palettes. (Need to register.) Or you can get the palette as an image that you can then use as a color swatch. (Open the image as a new file in GIMP and pick the color off the swatch with the Color Picker tool or with the Color Picker option in the Set Color dialog.) I saved the palette images (390x300 size) as swatches because I like the larger blocks of color that the swatch provides.
You could spend days browsing this site.
Edit: I thought I had covered all the possibilities for getting a single block of the pattern, but I had missed the easiest one!