Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
The original enhanced with some gradients.
Source Firkin
Green Background Pattern
Source V. Hartikainen
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin