More Textures
Dark Stripes@2X #40
 Dark  CC BY-SA 3.0

Very dark pattern with some noise and 45-degree lines.

Source Stefan Aleksić

Desert Camo Print #255
 Fabric  CC 0

Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.

Source Eady

Prismatic Dots Background 7@2X #514
 Dark  CC 0

Prismatic Dots Background 7

Source GDJ

Seamless Prismatic Pythagorean Line Art Pattern No Background@2X #570
 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

crissXcross@2X #112
 Dark  CC BY-SA 3.0

Dark pattern with some nice diagonal stitched lines crossing over.

Source Ashton

Colourful background #2010
 Colorful  CC 0

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

Source Firkin

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

Rice Paper #338
 Paper  CC BY-SA 3.0

Scanned some rice paper and tiled it up for you. Enjoy.

Source Atle Mo

Decorative divider 252 #2065
 Dark  CC 0

Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.

Source Firkin

Element of beach pattern with background #254
 Noise  CC 0

Element of beach pattern with background.

Source Rones

stone filter pack #154
 Stone  CC 0

This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.

Source Lazur URH

Merely Cubed #589
 Grid  CC BY-SA 3.0

Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.

Source Etienne Rallion

Vintage Elegant Floral Background #257
 Fabric  CC 0

PDP

Source GDJ

Prismatic Octagonal Background@2X #440
 Noise  CC 0

Prismatic Octagonal Background

Source GDJ

Prismatic Abstract Geometric Background 4 #271
 Noise  CC 0

Prismatic Abstract Geometric Background 4

Source GDJ

Graphene pattern 2 #2234
 Dark  CC 0

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

Source Firkin