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

 More Textures
Old Wall #346
 Wall  CC BY-SA 3.0

Old concrete wall in light shades.

Source Bartosz Kaszubowski

Background pattern 272 (colour 3) #2055
 Red  CC 0

A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

overlay crack #153
 Noise  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

Raindrop-seamless pattern #2558
 Blue  CC 0

This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.

Source Yamachem

Elegant Grid #316
 Wall  CC BY-SA 3.0

This is a hot one. Small, sharp and unique.

Source GraphicsWall

Prismatic Groovy Concentric Background 5 #465
 Dark  CC 0

Prismatic Groovy Concentric Background 5

Source GDJ

Mosaic Gems Background@2X #527
 Noise  CC 0

Mosaic Gems Background

Source GDJ

Diamond pattern (colour 5) #2281
 Red  CC 0

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

Source Firkin

Background pattern 328 (colour 2) #1800
 Green  CC 0

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

Source Firkin

Background pattern 269 #2062
 Dark  CC 0

A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i

Source Firkin