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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Green Web Background, Seamless tile.
Source V. Hartikainen
A seamless paper background colored in pale yellow.
Source V. Hartikainen
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
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
Prismatic Basic Pattern 2 No Background
Source GDJ
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Prismatic Abstract Geometric Background 2
Source GDJ
Prismatic Curved Diamond Pattern No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Prismatic Chevrons Pattern 5 With Background
Source GDJ
There are many carbon patterns, but this one is tiny.
Source Designova
This seamless light brown background texture resembles a wallpaper with vertical stripes. One way to use it is as a tiled background on web sites.
Source V. Hartikainen
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin