More Textures
45-Degree Fabric #1
 Fabric  CC BY-SA 3.0

Medium gray fabric pattern with 45-degree lines going across.

Source Atle Mo

Diamond pattern (colour 6) #2280
 Yellow  CC 0

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

Source Firkin

Retro Circles Background 8 No Black #437
 Dark  CC 0

Retro Circles Background 8 No Black

Source GDJ

Prismatic Polyskelion Pattern No Background #394
 Light  CC 0

Prismatic Polyskelion Pattern No Background

Source GDJ

Seamless Core Pattern 5 #169
 Dark  CC 0

Seamless Core Pattern 5

Source GDJ

Green Fibers #91
 Dark  CC BY-SA 3.0

The green fibers pattern will work very well in grayscale as well.

Source Matteo Di Capua

Background pattern 308 (colour 2) #1871
 Green  CC 0

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

Source Firkin

Background pattern 225 (colour 4) #2324
 Green  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

Subtle Freckles #89
 Light  CC BY-SA 3.0

This is so subtle: We’re talking 1% opacity. Get your squint on!

Source Atle Mo

Prismatic Abstract Geometric Background 4 No Black@2X #443
 Dark  CC 0

Prismatic Abstract Geometric Background 4

Source GDJ

Background pattern 306 (colour 3) #1880
 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

Old Wall #346
 Wall  CC BY-SA 3.0

Old concrete wall in light shades.

Source Bartosz Kaszubowski

Tileable Wave Pattern 2 remix #2490
 Dark  CC 0

This is the remix of "Tileable Wave Pattern 2" uploaded by "Arvin61r58".Thanks.I added a wire-mesh fence seamless pattern as a lower layer.

Source Yamachem