Yellow Wood Planks Background #876
 Wood  CC BY-SA 3.0

This background pattern contains a texture of yellow wood planks. I think it looks quite original.

Source V. Hartikainen

 More Textures
Green Fibers #91
 Dark  CC BY-SA 3.0

The green fibers pattern will work very well in grayscale as well.

Source Matteo Di Capua

Abstract Ellipses Background Grayscale #378
 Dark  CC 0

Abstract Ellipses Background Grayscale

Source GDJ

Stone Wall & Green #1534
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Prismatic Groovy Concentric Background 4 #461
 Noise  CC 0

Prismatic Groovy Concentric Background 4

Source GDJ

Background pattern 240 #2209
 Dark  CC 0

Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.

Source Firkin

Honey I’m Subtle #1038
 Gray  CC BY-SA 3.0

A mid-gray hexagon pattern.

Source Alex M. Balling

Rebel #829
 Dark  CC BY-SA 3.0

Not the Rebel alliance, but a dark textured pattern.

Source Hendrik Lammers

Door Rail & Black #1625
 Dark  CC 0

Manmade & Civilisation-Details. CC0 License.

Source Unknow

Stone Wall & Yellow #1573
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Decorative divider 212 #2343
 Dark  CC 0

Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.

Source Firkin

Leafy pattern 7 (colour) #1827
 Red  CC 0

Alternative colour scheme.

Source Firkin

Black Linen 2 #103
 Dark  CC BY-SA 3.0

A new take on the black linen pattern. Softer this time.

Source Atle Mo

Floral design 94 #1792
 Yellow  CC 0

From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.

Source Firkin

Background pattern 332 (version 2) #1740
 Blue  CC 0

The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i

Source Firkin

Parquet flooring pattern (colour 2) #2426
 Green  CC 0

A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.

Source Firkin

Background pattern 26 (black) #199
 Dark  CC 0

Pattern formed from simple shapes. Black version.

Source Firkin

Background pattern 234 (colour 2) #2258
 Green  CC 0

Drawn in Paint.net and vectorised in Vector Magic.

Source Firkin

Diagonal [email protected] #1007
 Gray  CC BY-SA 3.0

It has waves, so make sure you don’t get sea sickness.

Source CoolPatterns

Prismatic Geometric Tessellation Pattern No Background #551
 Noise  CC 0

Prismatic Geometric Tessellation Pattern No Background

Source GDJ

Wood Texgen 4 #1438
 Wood  CC 0

Gamedev - Wood Textures. CC0 License.

Source Davit Masia

[email protected] #778
 Light  CC BY-SA 3.0

Cubes as far as your eyes can see. You know, because they tile.

Source Jan Meeus

Stone Wall & Dark #1538
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Metal Pole Rusty & Light #1650
 Metal  CC 0

Metal-Rusty. CC0 License.

Source Unknow

Specular & Small Block #1642
 Metal  CC 0

Metal-Processed. CC0 License.

Source Unknow

Brushed Aluminum 4 #1392
 Metal  CC 0

Gamedev - Metal Textures. CC0 License.

Source Davit Masia

Diamond pattern 2 (colour 5) #2264
 Blue  CC 0

From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Abstract Arbitrary Geometric Background #497
 Noise  CC 0

Abstract Arbitrary Geometric Background derived from an image on Pixabay.

Source GDJ