"Polished Stone", Gray Background Pattern #1053
 Stone  CC BY-SA 3.0

A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).

Source V. Hartikainen

 More Textures
Background pattern 252 #2162
 Dark  CC 0

Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern 252 (colour 6) #2157
 Light  CC 0

Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Dark Wood@2X #321
 Wood  CC BY-SA 3.0

A beautiful dark wood pattern, superbly tiled.

Source Omar Alvarado

Background pattern 314 (colour 2) #1838
 Green  CC 0

The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin

Background pattern 115-seamless pattern #2514
 Blue  CC 0

This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.

Source Yamachem

Micro Carbon@2X #8
 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

Prismatic Curved Diamond Pattern 4 No Background@2X #542
 Diamond  CC 0

Prismatic Curved Diamond Pattern 4 No Background

Source GDJ

Checkered Light Emboss@2X #281
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

Prismatic Dots Background 4@2X #508
 Noise  CC 0

Prismatic Dots Background 4

Source GDJ

Vintage pattern 2 #2295
 Yellow  CC 0

Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern 66@2X #478
 Wall  CC 0

A background pattern drawn in Inkscape.

Source Firkin

Tessellation 15 (colour 3) #2220
 Red  CC 0

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

Source Firkin

Prismatic Abstract Geometric Background 3 #270
 Noise  CC BY-SA 3.0

Prismatic Abstract Geometric Background 3

Source GDJ