Background pattern 306 (colour 3) #1880
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

 More Textures
Cubes #133
 Light  CC BY-SA 3.0

This reminds me of Game Cube. A nice light 3D cube pattern.

Source Sander Ottens

Dark Blue Gray Wallpaper Texture #901
 Stripes  CC BY-SA 3.0

This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!

Source V. Hartikainen

Sponge A2-6 #2129
 Wall  CC 0

CC0 textures, backgrounds.

Source SliverKnight

Prismatic Geometric Tessellation Pattern 4 No [email protected] #558
 Noise  CC 0

Prismatic Geometric Tessellation Pattern 4 No Background

Source GDJ

Fall Leaves #243
 Fabric  CC 0

Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.

Source Eady

Green Subtle Web Texture #1334
 Green  CC BY-SA 3.0

A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).

Source V. Hartikainen

"Colorful Stripes", Diagonally Striped Background #903
 Stripes  CC BY-SA 3.0

This background pattern contains worn out colorful stripes as a texture.

Source V. Hartikainen

Square ornament 37 #2177
 Dark  CC 0

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

Source Firkin

Ribbon pattern 2 (version 2, colour 3) #2037
 Colorful  CC 0

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

Source Firkin

[email protected] #1112
 Light  CC BY-SA 3.0

I skipped number 3, because it wasn’t all that great. Sorry.

Source Dima Shiper

Decorative divider 194 #2478
 Dark  CC 0

From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.

Source Firkin

Zodiac pattern (black background) #267
 Dark  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. Version with black background.

Source Firkin

Wild [email protected] #989
 Dark  CC BY-SA 3.0

Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.

Source Badhon Ebrahim

Stone Wall & Yellow #1579
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

[email protected] #724
 Fabric  CC BY-SA 3.0

Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.

Source Janos Koos

White [email protected] #640
 Fabric  CC BY-SA 3.0

I took the liberty of using Dmitry’s pattern and made a version without perforation.

Source Atle Mo

Wavy background #2014
 Blue  CC 0

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

Source Firkin

Background pattern pink and colours #2032
 Colorful  CC 0

A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.

Source Firkin

Dark Stitched Leather Background #996
 Stripes  CC BY-SA 3.0

A seamless dark leather-like background texture with diagonal lines that look like stitches.

Source V. Hartikainen

Dark [email protected] #818
 Dark  CC BY-SA 3.0

Just to prove my point, here is a slightly modified dark version.

Source Atle Mo

Triangular Psychosis 2 #234
 Noise  CC 0

A colorful triangular background, variation 2.

Source GDJ

Background pattern 26 (black) #199
 Dark  CC 0

Pattern formed from simple shapes. Black version.

Source Firkin

Background pattern 271 #2058
 Dark  CC 0

Remixed from a drawing in 'The Canadian horticulturist', 1892

Source Firkin

Prismatic Dots Background [email protected] #510
 Noise  CC 0

Prismatic Dots Background 5

Source GDJ

[email protected] #826
 Light  CC BY-SA 3.0

Bit of a strange name on this one, but still nice. Tiny gray square things.

Source Carlos Valdez

Striped Fabric Pattern #998
 Stripes  CC BY-SA 3.0

A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.

Source V. Hartikainen

Escheresque Dark #1064
 Dark  CC BY-SA 3.0

A comeback for you: the popular Escheresque, now in black.

Source Patten