That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
A free seamless background with pink spots.
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
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Fix side and a seamless pattern formed from circles.
Source SliverKnight