Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
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
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Continuing the geometric trend, here is one more.
Source Mike Warner
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
This one needs to be used in small areas; you can see it repeat.
Source Luca
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
This light background pattern has a texture of "frozen" surface with diagonal stripes. Here's an yet another addition to the collection of free website backgrounds.
Source V. Hartikainen
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin