Tessellation 16 (colour 4) #2212
 Green  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

 More Textures
Retro Circles Background 6@2X #429
 Noise  CC 0

Retro Circles Background 6

Source GDJ

Background pattern 309 (colour 2) #1865
 Blue  CC 0

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

Source Firkin

Background pattern 208 (colour 2) #2462
 Grid  CC 0

A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Ravenna #354
 Wall  CC BY-SA 3.0

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

Source Sentel

Pinstripe #35
 Light  CC BY-SA 3.0

Light gray pattern with a thin pinstripe.

Source Brandon

Seamless Prismatic Pythagorean Line Art Pattern No Background #569
 Light  CC 0

Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).

Source GDJ

Colourful background #2009
 Colorful  CC 0

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

Source Firkin

Concrete Wall #77
 Wall  CC BY-SA 3.0

Dark blue concrete wall with some small dust spots.

Source Atle Mo

Prismatic Curved Diamond Pattern 2 No Background #538
 Diamond  CC 0

Prismatic Curved Diamond Pattern 2 No Background

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

Bird pattern (colour 2) #2292
 Green  CC 0

Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

Black Mamba@2X #58
 Dark  CC BY-SA 3.0

The name alone is awesome, but so is this sweet dark pattern.

Source Federica Pelzel

Leafy design 18 (colour)@2XaFloral design 96 (colour) #1787
 Green  CC 0

From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.

Source Firkin

Prismatic Groovy Concentric Background 2 #453
 Noise  CC 0

Prismatic Groovy Concentric Background 2

Source GDJ