Based on an image that was uploaded to Pixabay by devanath
Source Firkin
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Prismatic Basic Pattern 2 No Background
Source GDJ
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Same classic 45-degree pattern, dark version.
Source Luke McDonald
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Almost like little fish shells, or dragon skin.
Source Graphiste
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
A seamless background tile of aged paper with shabby look.
Source V. Hartikainen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
Green Web Background, Seamless tile.
Source V. Hartikainen
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
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