Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 4
Source GDJ
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Neat little photography icon pattern.
Source Hossam Elbialy
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
A background pattern with a look of rough fabric.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This could be a hippy vintage wallpaper.
Source Tileable Patterns
A pale olive green background with a seamless texture.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
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
Colour version of the original seamless pattern.
Source Firkin
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin