A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
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
Seamless SVG vector and JPG backgrounds with faded diagonal stripes. The colors are editable.
Source V. Hartikainen
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Zero CC tillable hard cover red book with X shape marks. Scanned and made by me.
Source Sojan Janso
Pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus