Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
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
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 2
Source GDJ
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
A pale olive green background with a seamless texture.
Source V. Hartikainen
The image depicts a pattern of regular hexagon.As I made to use it for myself,I want to others to use it.Speaking about the ratio of the image, height : width = 2 : √3(1.732...)Ridiculous to say,I realized later that this image is not honey comb pattern.I have to slide the second row.
Source Yamachem
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Prismatic Hypnotic Pattern No Background
Source GDJ
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen