Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Black brick wall pattern. Brick your site up!
Source Alex Parker
I’m not going to use the word Retina for all the new patterns, but it just felt right for this one. Huge wood pattern for ya’ll.
Source Atle Mo
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Retro Circles Background 8 No Black
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A cute x, if you need that sort of thing.
Source Juan Scrocchi
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin