You can find many really free seamless background on AVA7 Patterns. There are over 150 pages with 4 beautiful patterns on every single page. You can set the current background with that specific pattern if you clicked on “Preview”. So that you can have a look at what it will look like on the actual site. And simply click on “Download” in order to download the pattern on your computer.

Free Seamless Background

Requirements: -
Demo: http://patterns.ava7.com/
License: License Free