Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
The image is a design of blue glass.How about using it as background image?
Source Yamachem
A gray background pattern with a texture of textile. Suits perfectly for web design.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Prismatic Curved Diamond Pattern 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
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Pattern formed from simple shapes. Black version.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Found on the ground in french cafe in kunming, Yunnan, china
Source Rejon
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin