This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Sharp pixel pattern, just like the good old days.
Source Paridhi
A comeback for you: the popular Escheresque, now in black.
Source Patten
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
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
This one is amazing, truly original. Go use it!
Source Viahorizon
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
If you want png files of thisu can download them here :
Source Viscious-Speed
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin