A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Sharp but soft triangles in light shades of gray.
Source Pixeden
Prismatic Abstract Line Art Pattern Background
Source GDJ
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
The image is a design of blue glass.How about using it as background image?
Source Yamachem
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors