It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Background Wall, Art Abstract, Star Well & CC0 texture.
Source Ractapopulous
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
Abstract Tiled Background Extended 12
Source GDJ
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Light and tiny, just the way you like it.
Source Rohit Arun Rao