Subtle scratches on a light gray background.
Source Andrey Ovcharov
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
From a tile that can be had 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
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
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 background pattern with a look of rough fabric.
Source V. Hartikainen
Sharp pixel pattern, just like the good old days.
Source Paridhi
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Abstract Tiled Background Extended 11
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
This was formed by distorting an image of a background on Pixabay.
Source Firkin