Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter