Dark blue concrete wall with some small dust spots.
Source Atle Mo
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A comeback for you: the popular Escheresque, now in black.
Source Patten
Retro Circles Background 8 No Black
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
One more sharp little tile for you. Subtle circles this time.
Source Blunia
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin