Medic Packaging Foil@2X #377
 Light  CC BY-SA 3.0

8 by 8 pixels, and just what the title says.

Source pixilated

 More Textures
Elegant Grid #316
 Wall  CC BY-SA 3.0

This is a hot one. Small, sharp and unique.

Source GraphicsWall

White Texture@2X #132
 Light  CC BY-SA 3.0

Not the most creative name, but it’s a good all-purpose light background.

Source Dmitry

Squares@2X #303
 Dark  CC BY-SA 3.0

Dark, square, clean and tidy. What more can you ask for?

Source Jaromír Kavan

Retro Circles Background 4@2X #421
 Dark  CC 0

Retro Circles Background 4

Source GDJ

Background pattern 7 #227
 Noise  CC 0

Pattern that came out of playing with the 'slinky' plug-in for Paint.net

Source Firkin

Little Pluses@2X #74
 Light  CC BY-SA 3.0

Subtle grunge and many little pluses on top.

Source Atle Mo

Hexagonal pattern (colour) #2378
 Yellow  CC 0

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

Source Firkin

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

Street Art Pattern #1196
 Concrete  CC BY-SA 3.0

Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.

Source V. Hartikainen