Light Aluminum #304
 Wall  CC BY-SA 3.0

Used correctly, this could be nice. Used in a bad way, all hell will break loose.

Source Atle Mo

 More Textures
Background pattern 332 (version 2) #1740
 Blue  CC 0

The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i

Source Firkin

Ravenna@2X #355
 Wall  CC BY-SA 3.0

I guess this is inspired by the city of Ravenna in Italy and its stone walls.

Source Sentel

Broken Noise #364
 Dark  CC BY-SA 3.0

Beautiful dark noise pattern with some dust and grunge.

Source Vincent Klaiber

Background pattern 272 (colour 2) #2056
 Pink  CC 0

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

Source Firkin

Background pattern 239 #2217
 Red  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Colorful Geometric Pattern Background #231
 Noise  CC 0

PDP

Source GDJ

Seamless 3D Isometric Tessellation Pattern 2 #147
 Light  CC 0

A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).

Source GDJ

Paper texture filter #149
 Paper  CC 0

Filter simulating the texture of heavy paper.

Source Kelan

Tessellation 9 #2548
 Grid  CC 0

A seamless tessellation pattern. To get the tile this is formed from, select the pattern in Inkscape and use shift+alt+i.

Source Firkin

Retro Squares Background #414
 Noise  CC 0

Retro Squares Background

Source GDJ