Background pattern green #1944
 Green  CC 0

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

Source Firkin

 More Textures
Leather 1 #13
 Light  CC BY-SA 3.0

A leather pattern with a hint of yellow.

Source Atle Mo

Prismatic Hexagonalist Pattern No Background #390
 Light  CC 0

Prismatic Hexagonalist Pattern No Background

Source GDJ

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

Tessellation 16 (colour 5) #2211
 Yellow  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

Background pattern 9 (greyscale) #213
 Dark  CC BY-SA 3.0

Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net

Source Firkin

Background pattern 306 (colour 2) #1881
 Colorful  CC 0

Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.

Source Firkin

Seamless Cardboard Texture #1212
 Cardboard  CC BY-SA 3.0

A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.

Source V. Hartikainen

Background pattern 201 (colour 2) #2496
 Grid  CC 0

A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.

Source Firkin

Soft Kill@2X #319
 Dark  CC BY-SA 3.0

Pattern #100! A black classic knit-looking pattern.

Source Factorio.us Collective

Prismatic Abstract Line Art Pattern Background@2X #566
 Dark  CC 0

Prismatic Abstract Line Art Pattern Background

Source GDJ

Background pattern 225 (colour 5) #2323
 Blue  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

Fabric 1 #9
 Light  CC BY-SA 3.0

Semi-light fabric pattern made out of random pixels in shades of gray.

Source Atle Mo

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

Dark pattern with some nice diagonal stitched lines crossing over.

Source Ashton

Rice Paper 2@2X #341
 Paper  CC BY-SA 3.0

One can never have too few rice paper patterns, so here is one more.

Source Atle Mo