I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Lovely pattern with splattered vintage speckles.
Source David Pomfret
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
U.S.-based National Fire Protection Association standard fire diamond for flagging risks posed by hazardous materials. The red diamond has a number 0-4 depending on flammability. The blue diamond has a number 0-4 depending on health hazard. The yellow has a number 0-4 depending on reactivity. the white square has a special notice, e.g OX for oxidizer.
Source Firkin
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A free web background image with a seamless concrete-like texture and an Indian-red color.
Source V. Hartikainen
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
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
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Basic Pattern 2 No Background
Source GDJ
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Derived from a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin