Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
The original enhanced with some gradients.
Source Firkin
The name is totally random, but hey, it sounds good.
Source Atle Mo
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
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
Seamless Green Tile Background
Source V. Hartikainen
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem