1. Stripe Generator. This is a nifty little tool you won't be able to get enough of. Be aware, you'll need photoshop to download your background. The Stripe Generator has practically everything you could want. Size. Spacing. Background color. Style. Straight lines. Diagonal lines.
2. Color Scheme Generator 2. This is exactly what the name implies: a color scheme generator. It is very useful, and it has an option to show "web safe colors" so that everyone can see your layout exactly as you do. You have lots of variations. You can choose, for example, if you want your green pale, pastel, contrast, etc. Different shades. (My favorites are the greens and warms colors under the pale variations.)
3. Inkscape. This is an open-source vector program. It is like Adobe Illustrator. And anyone, like me, who is broke - Inkscape is a great alternative to the monstrously expensivle Illustrator. This program uses the SVG file format, but it isn't chalked up with all the features that you know and love like from your other programs. But this is also free, and less than 40 megabytes. It is growing in features, but it can still perform all of your basic vector needs. So, for anyone that wants to include vector-art graphics for your lj, this is a good choice.
More resources are soon to come. I will work on all of them later, and I'll add onto this post.