Background pattern 309 (colour 2) #1865
 Blue  CC 0

Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.

Source Firkin

 More Textures
Fake Brick #358
 Dark  CC BY-SA 3.0

Black, simple, elegant, and useful.

Source Marat

Paven@2X #297
 Grid  CC BY-SA 3.0

A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.

Source Josh Green

Black Linen #63
 Dark  CC BY-SA 3.0

In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.

Source Atle Mo

Patern dots #241
 Dark  CC 0

Pattern repeating background 48x48

Source Keistutis

Green Gobbler@2X #86
 Dark  CC BY-SA 3.0

Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.

Source Simon Meek

Triangles pattern #2408
 Brown  CC 0

A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

Black And White Floral Pattern Background Inverse #196
 Dark  CC 0

Black And White Floral Pattern Background Inverse

Source GDJ

Tessellation 15 (colour 3) #2220
 Red  CC 0

The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.

Source Firkin

Noisy@2X #46
 Paper  CC BY-SA 3.0

Looks a bit like concrete with subtle specks spread around the pattern.

Source Mladjan Antic

Concrete Wall 2 #79
 Wall  CC BY-SA 3.0

A light gray wall or floor (you decide) of concrete.

Source Atle Mo

Diamond pattern 2 (colour 4) #2265
 Red  CC 0

From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Background pattern 24 #198
 Dark  CC 0

The starting point for this was a texture drawn with the 'Radial Colors' plug-in in Paint.net.

Source Firkin

Background pattern 6 #226
 Noise  CC 0

A pattern derived from part of a fractal rendering in Paint.net.

Source Firkin

Lined Paper #362
 Stripes  CC BY-SA 3.0

The classic notebook paper with horizontal stripes.

Source Are Sundnes