Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
A yellow tiled background... Blurriness, bokeh effect and rectangles pattern in one mix.
Source V. Hartikainen
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A seamless pattern formed from background pattern 102
Source Firkin
This one has rusty dark brown texture.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
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
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin