A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from a vector adapted from a jpg on Pixabay. The tile this is constructed from can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Seamless Prismatic Quadrilateral Line Art Pattern No Background
Source GDJ
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal