Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Tiny circle waves, almost like the ocean.
Source Sagive
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
Prismatic Abstract Geometric Background 2 No Black
Source GDJ