45-Degree Fabric #1
 Fabric  CC BY-SA 3.0

Medium gray fabric pattern with 45-degree lines going across.

Source Atle Mo

 More Textures
Background pattern #2000
 Dark  CC 0

Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Background pattern 225 (colour 6) #2322
 Brown  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

Retro Circles Background 5@2X #425
 Noise  CC 0

Retro Circles Background 5

Source GDJ

Paven #296
 Grid  CC BY-SA 3.0

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

Source Josh Green

Prismatic Polka Dots Mark II 2 No Background@2X #533
 Noise  CC 0

Prismatic Polka Dots Mark II 2 No Background

Source GDJ

Lego background #2428
 Colorful  CC 0

Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.

Source Firkin

Diamond pattern (colour 6) #2280
 Yellow  CC 0

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

Source Firkin

Decorative divider 194 #2478
 Dark  CC 0

From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.

Source Firkin

Prismatic Dots Background 5 #509
 Noise  CC 0

Prismatic Dots Background 5

Source GDJ

Background pattern 308 (colour 4) #1868
 Green  CC 0

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

Source Firkin