Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
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
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Black brick wall pattern. Brick your site up!
Source Alex Parker
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc