I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
It’s big, it’s gradient—and it’s square.
Source Brankic1979
Abstract Ellipses Background Grayscale
Source GDJ
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A nice and simple white rotated tile pattern.
Source Another One
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
An alternative colour scheme for the original background.
Source Firkin
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ