Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Alternative colour scheme. 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
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Background formed from the original with an emboss effect
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts