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
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Basket Fibers, Basket Texture, Braid Background style CC0 texture.
Source 1A-Photoshop
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Zero CC asphalt, pavement, texture, photographed and made by me. CC0 WARNING I FOUND A SEAM ON THIS TEXTURE
Source Sojan Janso
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
Retro Circles Background 5 No Black
Source GDJ
This background pattern contains a texture of yellow wood planks. I think it looks quite original.
Source V. Hartikainen