This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
This background texture resembles stone. It may be used as a background on web pages or on some of their html elements (header, borders, menu bar, etc.). Just modify it for your needs.
Source V. Hartikainen
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Plywood Web Background background image for use in web design.
Source V. Hartikainen
There are many carbon patterns, but this one is tiny.
Source Designova
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin