Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Black brick wall pattern. Brick your site up!
Source Alex Parker
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
Prismatic Abstract Geometric Background 3
Source GDJ
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
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
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Oh yes, it happened! A pattern in full color.
Source Atle Mo
Prismatic Abstract Line Art Pattern Background 2
Source GDJ