Background pattern 225 (colour 6) #2322
 Brown  CC 0

Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.

Source Firkin

 More Textures
Light Honeycomb #59
 Light  CC BY-SA 3.0

Light honeycomb pattern made up of the classic hexagon shape.

Source Federica Pelzel

Background pattern 308 (colour 4) #1868
 Green  CC 0

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

Source Firkin

Starting Diamond Shape@2X #138
 Light  CC 0

Simple blue and line to mix.

Source SliverKnight

Gray Sand #17
 Dark  CC BY-SA 3.0

A dark gray, sandy pattern with small light dots, and some angled strokes.

Source Atle Mo

Background pattern 235 (colour 2) #2254
 Blue  CC 0

To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Diamond pattern (colour 3) #2283
 Green  CC 0

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

Source Firkin

Background pattern 224 (colour 5) #2338
 Colorful  CC 0

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

Source Firkin

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

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