Glass block pattern #2477
 Brown  CC 0

Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.

Source Firkin

 More Textures
Little Pluses #73
 Light  CC BY-SA 3.0

Subtle grunge and many little pluses on top.

Source Atle Mo

Dark Brick Wall@2X #136
 Wall  CC BY-SA 3.0

Black brick wall pattern. Brick your site up!

Source Alex Parker

Colorful Geometric Pattern Background #231
 Noise  CC 0

PDP

Source GDJ

Background pattern 207 (colour 2) #2464
 Colorful  CC 0

A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern 256 #2139
 Red  CC 0

Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i

Source Firkin

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

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

Source Atle Mo

Geometric pattern #2005
 Grid  CC 0

A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i

Source Firkin

Prismatic Dots Background 2 #503
 Noise  CC 0

Prismatic Dots Background 2

Source GDJ

Micro Carbon #7
 Carbon  CC BY-SA 3.0

Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.

Source Atle Mo

Rice Paper@2X #339
 Paper  CC BY-SA 3.0

Scanned some rice paper and tiled it up for you. Enjoy.

Source Atle Mo