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 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
The classic notebook paper with horizontal stripes.
Source Are Sundnes
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin
This is a grid, only it’s noisy. You know. Reminds you of those printed grids you draw on.
Source Vectorpile
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
The image is a seamless pattern of a fishnet.
Source Yamachem
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Geometric triangles seem to be quite hot these days.
Source Pixeden
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin