Background pattern 26 (black) #199
 Dark  CC 0

Pattern formed from simple shapes. Black version.

Source Firkin

 More Textures
Background pattern 1 #220
 Noise  CC 0

A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.

Source Firkin

Prismatic Polka Dots Mark II 3 No Background #534
 Noise  CC 0

Prismatic Polka Dots Mark II 3 No Background

Source GDJ

Retina Dust@2X #916
 Light  CC BY-SA 3.0

First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.

Source Atle Mo

Background pattern 269 #2062
 Dark  CC 0

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

Source Firkin

Lined Paper #362
 Stripes  CC BY-SA 3.0

The classic notebook paper with horizontal stripes.

Source Are Sundnes

Background pattern 239 #2218
 Dark  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Pool Table@2X #176
 Wall  CC BY-SA 3.0

This makes me wanna shoot some pool! Sweet green pool table pattern.

Source Caveman

Prismatic Groovy Concentric Background No Black #451
 Noise  CC 0

Prismatic Groovy Concentric Background No Black

Source GDJ

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

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

Source Firkin

Background pattern purple #1952
 Colorful  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Desert Camo Print #255
 Fabric  CC 0

Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.

Source Eady