Dark Stripes@2X #40
 Dark  CC BY-SA 3.0

Very dark pattern with some noise and 45-degree lines.

Source Stefan Aleksić

 More Textures
Triangular Psychosis 4 #236
 Noise  CC 0

A colorful triangular background, variation 4.

Source GDJ

Transparent Square Tiles #298
 Grid  CC BY-SA 3.0

The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.

Source Nathan Spady

Wood Pattern #370
 Wood  CC BY-SA 3.0

One of the few full-color patterns here, but this one was just too good to pass up.

Source Alexey Usoltsev

Project Papper@2X #120
 Paper  CC BY-SA 3.0

Light square grid pattern, great for a “DIY projects” sort of website, maybe?

Source Rafael Almeida

Prismatic Abstract Line Art Pattern Background #565
 Dark  CC 0

Prismatic Abstract Line Art Pattern Background

Source GDJ

Soft Circle Scales@2X #114
 Light  CC BY-SA 3.0

Japanese looking fish scale pattern.

Source Ian Soper

Retro Circles Background 8@2X #436
 Dark  CC 0

Retro Circles Background 8

Source GDJ

Background pattern 224 (colour 2) #2341
 Colorful  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

Abstract Tiled Background Extended 10 #521
 Noise  CC 0

Abstract Tiled Background Extended 10

Source GDJ

"Pink Bump Dots", Background Tile #1234
 Pink  CC BY-SA 3.0

A free background tile with a pattern of pink bump dots. This background tile is sweet! Moreover, it's designed for use as website backgrounds.

Source V. Hartikainen

Decorative divider 271 #1923
 Dark  CC 0

Remixed from a drawing in 'Incidents on a Journey through Nubia to Darfoor', F. Ensor, 1891.

Source Firkin