The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
From a drawing in 'Jardyne's Wife', Charles Wills, 1891.
Source Firkin
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This one looks like a cork panel. Feel free to use it as a tiled background on your blog or website.
Source V. Hartikainen
Black paper texture, based on two different images.
Source Atle Mo
Based from Design Kindle
Looks like an old wall. I guess that’s it then?
Source Viahorizon
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
This one needs to be used in small areas; you can see it repeat.
Source Luca
Spice up your next school project with this icon background.
Source Swetha