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 pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free pink background pattern.
Source V. Hartikainen
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen
From a drawing in 'Friend or Fortune? The story of a strange year', Robert Overton, 1897.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Background formed from the original with an emboss effect.
Source Firkin
This is the remix of "Colorful Floral Pattern Background 3" uploaded by "GDJ". Thanks.
Source Yamachem
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
A version without colours blended together to give a different look.
Source Firkin