Number five from the same submitter, makes my job easy.
Source Dima Shiper
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
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
It’s big, it’s gradient—and it’s square.
Source Brankic1979
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
This was submitted in a beige color, hence the name. Now it’s a gray paper pattern.
Source Konstantin Ivanov
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Used a cherry by doctormo to make this seamless pattern
Source Firkin
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A bit of scratched up grayness. Always good.
Source Dmitry
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc