Background pattern 5 #224
 Noise  CC 0

A pattern drawn in Paint.net and vectorized in Inkscape.

Source Firkin

 More Textures
Black Paper #55
 Dark  CC BY-SA 3.0

Black paper texture, based on two different images.

Source Atle Mo
Based from Design Kindle

Diamond pattern 2 (colour 5) #2264
 Blue  CC 0

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

Source Firkin

Fake Brick@2X #359
 Dark  CC BY-SA 3.0

Black, simple, elegant, and useful.

Source Marat

Random Grey Variations #69
 Stripes  CC BY-SA 3.0

Stefan is hard at work, this time with a funky pattern of squares.

Source Stefan Aleksić

"Dark Metal Plate", Web Background #1084
 Metal  CC BY-SA 3.0

A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.

Source V. Hartikainen