This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
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
The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:https://jp.pinterest.com/pin/500744052301423641/
Source Yamachem
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Dark blue concrete wall with some small dust spots.
Source Atle Mo
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
This background pattern has futuristic look. So, maybe it could be used on websites or blogs dedicated to video games?!
Source V. Hartikainen
A bit of scratched up grayness. Always good.
Source Dmitry