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
Looks like an old rug or a computer chip.
Source Patutin Sergey
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Colorful Floral Background No Black
Source GDJ
Tiny circle waves, almost like the ocean.
Source Sagive
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
So tiny, just 7 by 7 pixels – but still so sexy. Ah yes.
Source Dmitriy Prodchenko
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Abstract Ellipses Background Grayscale
Source GDJ
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell