Seamless Core Pattern 2 #166
 Dark  CC 0

Seamless Core Pattern 2

Source GDJ

 More Textures
Background pattern 308 (colour 3) #1870
 Colorful  CC 0

Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.

Source Firkin

Light Aluminum@2X #305
 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

Abstract Tiled Background Extended 12 #523
 Noise  CC 0

Abstract Tiled Background Extended 12

Source GDJ

Carbon Fiber Big@2X #327
 Carbon  CC BY-SA 3.0

Bigger is better, right? So here you have some large carbon fiber.

Source Factorio.us Collective

Checkered Light Emboss #280
 Grid  CC BY-SA 3.0

Sort of like the Photoshop transparent background, but better!

Source Alex Parker

"Maple", Seamless Wood Texture #883
 Wood  CC BY-SA 3.0

Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.

Source V. Hartikainen

Fleurs-de-lys pattern 2 #2205
 Dark  CC 0

Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.

Source Firkin

Dark Denim #29
 Dark  CC BY-SA 3.0

A dark denim looking pattern. 145×145 pixels.

Source Atle Mo

Colourful background #2011
 Colorful  CC 0

Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic

Source Firkin

Prismatic Chevrons Pattern 5 With Background@2X #470
 Dark  CC 0

Prismatic Chevrons Pattern 5 With Background

Source GDJ

Exclusive Paper@2X #24
 Light  CC BY-SA 3.0

Paper pattern with small dust particles and 45-degree strokes.

Source Atle Mo

Tactile Noise@2X #6
 Dark  CC BY-SA 3.0

A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.

Source Atle Mo

Background pattern 315 (colour 6) #1840
 Green  CC 0

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

Source Firkin