It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Embossed lines and squares with subtle highlights.
Source Alex Parker
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
No, not the band but the pattern. Simple squares in gray tones, of course.
Source Atle Mo
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin