Green Tiles, Background Pattern #1329
 Green  CC BY-SA 3.0

A free background pattern with abstract green tiles.

Source V. Hartikainen

 More Textures
Perforated White [email protected] #636
 Light  CC BY-SA 3.0

A bit of scratched up grayness. Always good.

Source Dmitry

Wavy background #2012
 Green  CC 0

A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic

Source Firkin

Colorful Stripes Background #400
 Noise  CC 0

Colorful Stripes Background

Source GDJ

Retro Squares Background 5 #395
 Dark  CC 0

Retro Squares Background 5

Source GDJ

Flying swan pattern #1978
 Blue  CC 0

Remixed from a drawing in 'Line and form', Walter Crane, 1914.

Source Firkin

Debut Dark #1014
 Dark  CC BY-SA 3.0

Same classic 45-degree pattern, dark version.

Source Luke McDonald

Floral background 2 #2471
 Yellow  CC 0

Background formed from the original with an emboss effect.

Source Firkin

Soft Circle Scales #113
 Light  CC BY-SA 3.0

Japanese looking fish scale pattern.

Source Ian Soper

Decorative divider 251 #2069
 Dark  CC 0

Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.

Source Firkin

Carbon Fiber [email protected] #327
 Carbon  CC BY-SA 3.0

Bigger is better, right? So here you have some large carbon fiber.

Source Factorio.us Collective

Retro Squares Background [email protected] #417
 Noise  CC 0

Retro Squares Background 2

Source GDJ

Background pattern 315 (colour 4) #1842
 Colorful  CC 0

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

Source Firkin

Leafy pattern #2335
 Dark  CC 0

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

Source Firkin

Seamless Green Tile Background #1326
 Green  CC BY-SA 3.0

Seamless Green Tile Background

Source V. Hartikainen

Floral background 11 #2044
 Dark  CC 0

Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.

Source Firkin

Rough [email protected] #313
 Fabric  CC BY-SA 3.0

More tactile goodness. This time in the form of some rough cloth.

Source Bartosz Kaszubowski

Cutcube #629
 Diamond  CC BY-SA 3.0

Cubes, geometry, 3D. What’s not to love?

Source Michael Atkins

Seamless tile 4 #1812
 Red  CC 0

Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern

Source Firkin

Decorative divider 226 #2178
 Dark  CC 0

Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.

Source Firkin

Floral pattern 16 #1755
 Dark  CC 0

A pattern of alternating squares

Source Firkin

Food #1300
 Yellow  CC BY-SA 3.0

Holy mackerel, it’s colorful—but still subtle.

Source Ilya

Prismatic Geometric Pattern Background [email protected] #785
 Noise  CC 0

Prismatic Geometric Pattern Background 2

Source GDJ

"Dark Red Canvas", Seamless Web Texture #1221
 Red  CC BY-SA 3.0

A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.

Source V. Hartikainen

Abstract Water Texture (Seamless) #890
 Water  CC BY-SA 3.0

An abstract texture of water. It's not perfect, but will do. You may download if you like it.

Source V. Hartikainen

Decorative divider 238 #2088
 Dark  CC 0

From a drawing in 'The Quiver of Love', Walter Crane, 1876

Source Firkin

Fabric of [email protected] #1096
 Light  CC BY-SA 3.0

As far as fabric patterns goes, this is quite crisp.

Source Heliodor Jalba

[email protected] #928
 Dark  CC BY-SA 3.0

A very dark asfalt pattern based off of a photo taken with my iPhone.

Source Atle Mo

Fleurs-de-lys pattern 2 (colour) #2204
 Colorful  CC 0

Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.

Source Firkin

Merely [email protected] #590
 Grid  CC BY-SA 3.0

Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.

Source Etienne Rallion