As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Abstract Tiled Background Extended 10
Source GDJ
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Sharp pixel pattern, just like the good old days.
Source Paridhi
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
You guessed it – looks a bit like cloth.
Source Peax Webdesign
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ