It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Nicely executed tiling for an interesting pattern.
Source Ignasi Àvila Padró
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Sharp but soft triangles in light shades of gray.
Source Pixeden
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
This background has abstract texture with some similarities to wood.
Source V. Hartikainen