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
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Prismatic Abstract Background Design No Black
Source GDJ
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
A simple bump filter made upon request at irc #inkscape at freenode. Made a screen capture of the making here: https://youtu.be/TGAWYKVLxQw
Source Lazur URH
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin