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
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
This is the remix of "blue wave-seigaiha".This is the flowers of pink silk tree which is called "nemuno-ki".About pink silk tree ,refer to here:https://jp.pinterest.com/pin/500744052301210439/
Source Yamachem
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Chevrons Pattern 5 With Background
Source GDJ
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Abstract Tiled Background Extended 12
Source GDJ
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Retro Circles Background 4 No Black
Source GDJ
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Very simple, very blu(e). Subtle and nice.
Source Seb Jachec