Embossed lines and squares with subtle highlights.
Source Alex Parker
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Classic vertical lines, in all its subtlety.
Source Cody L
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
Original minus the background
Source Firkin
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
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 tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Abstract Tiled Background Extended 10
Source GDJ