My Little Plaid@2X #333
 Light  CC BY-SA 3.0

Repeating squares overlapping.

Source Pete Fecteau

 More Textures
Glass block pattern #2477
 Brown  CC 0

Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.

Source Firkin

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

Background pattern 214 (colour 6) #2372
 Colorful  CC 0

A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.

Source Firkin

Art Nouveau ornament-seamless pattern #2550
 Brown  CC 0

This is the remix of an OCAL clipart called "Art Nouveau ornament" uploaded by "microcosme".Thanks.This is a seamless pattern of an Art Nouveau ornament.

Source Yamachem

Dark Stripes #39
 Dark  CC BY-SA 3.0

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

Source Stefan Aleksić

Pinetree in tortoiseshell(亀甲松) #2538
 Dark  CC 0

The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/

Source Yamachem