Dark Steel Grid Background Pattern #1081
 Metal  CC BY-SA 3.0

Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!

Source V. Hartikainen

 More Textures
Mosaic tile #2481
 Brown  CC 0

From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.

Source Firkin

Pinetree in tortoiseshell(亀甲松) #2538
 Dark  CC 0

The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/

Source Yamachem

Retro Circles Background 6@2X #429
 Noise  CC 0

Retro Circles Background 6

Source GDJ

Prismatic Curved Diamond Pattern 8 No Background@2X #550
 Dark  CC 0

Prismatic Curved Diamond Pattern 8 No Background

Source GDJ

Prismatic Abstract Geometric Background 2 No Black #445
 Noise  CC 0

Prismatic Abstract Geometric Background 2 No Black

Source GDJ

Triangular Psychosis 2 #234
 Noise  CC 0

A colorful triangular background, variation 2.

Source GDJ

Background pattern 314 (colour 3) #1837
 Green  CC 0

The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Prismatic Groovy Concentric Background 5 #465
 Dark  CC 0

Prismatic Groovy Concentric Background 5

Source GDJ

Light Orange Brown Wallpaper #911
 Stripes  CC BY-SA 3.0

A free light orange brown wallpaper with vertical stripes designed for use as a tiled background on websites. An yet another background pattern with vertical stripes.

Source V. Hartikainen

Background pattern 6 #226
 Noise  CC 0

A pattern derived from part of a fractal rendering in Paint.net.

Source Firkin