This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Fix side and a seamless pattern formed from circles.
Source SliverKnight
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
A seamlessly tileable pink background texture.
Source V. Hartikainen
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
A seamless textured paper for backgrounds. Colored in pale orange hues.
Source V. Hartikainen
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A new take on the black linen pattern. Softer this time.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Zero CC tileable yellow craft paper; scanned and made by me. CC0
Source Sojan Janso
Seamless Olive Green Web Background Image
Source V. Hartikainen
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin