As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
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
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
"Beige Stone", Tileable Texture.
Source V. Hartikainen
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering