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
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A floral background formed from numerous clones of flower 117.
Source Firkin
Same classic 45-degree pattern, dark version.
Source Luke McDonald
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
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
This one has rusty dark brown texture.
Source V. Hartikainen
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns