Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
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
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A background pattern with wavy green vertical stripes. This one has green stripes on a white background. Download if you like it.
Source V. Hartikainen
Light and tiny, just the way you like it.
Source Rohit Arun Rao
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo